diff --git a/backend/ar/user.json b/backend/ar/user.json
index 52a8379d..2e37cca7 100644
--- a/backend/ar/user.json
+++ b/backend/ar/user.json
@@ -135,6 +135,7 @@
         "contact_persons_in_museum": "Contact persons in museum",
         "contact_person_in_museum_explica": "If this switch is set to yes, the user's name and mail address (and, if the profile is set visible within musdb) will appear in the navigation as a contact for colleagues asking for help.",
         "no_email_set": "No email address has been entered",
-        "user_address_on_blocked_domain": "The user address is hosted by a blocked mail hoster:"
+        "user_address_on_blocked_domain": "The user address is hosted by a blocked mail hoster:",
+        "mail_invalid_domain": "The entered email addresses' domain seems to be invalid."
     }
 }
\ No newline at end of file
diff --git a/backend/de/user.json b/backend/de/user.json
index 9b04cf76..d189820c 100644
--- a/backend/de/user.json
+++ b/backend/de/user.json
@@ -135,6 +135,7 @@
         "contact_persons_in_museum": "Kontaktpersonen (Museum)",
         "contact_person_in_museum_explica": "Ist dieser Schalter aktiviert, werden der Name und die Mailadresse des Benutzers - und, falls das Profil innerhalb von musdb auf Sichtbar geschaltet ist, auch ein Link zum Profil - in der Navigation als Kontakte f\u00fcr hilfesuchende Kollegen innerhalb des Museums angezeigt.",
         "no_email_set": "Es wurde keine e-Mail-Addresse angegeben",
-        "user_address_on_blocked_domain": "Die Mailadresse des Benutzers wird von einem nicht unterst\u00fctzten Mailserver gehostet: "
+        "user_address_on_blocked_domain": "Die Mailadresse des Benutzers wird von einem nicht unterst\u00fctzten Mailserver gehostet: ",
+        "mail_invalid_domain": "Die Domain der eingegebenen Email-Adresse scheint nicht valide zu sein."
     }
 }
\ No newline at end of file
diff --git a/backend/dsb/user.json b/backend/dsb/user.json
index 2053beed..24e607ea 100644
--- a/backend/dsb/user.json
+++ b/backend/dsb/user.json
@@ -135,6 +135,7 @@
         "contact_persons_in_museum": "Contact persons in museum",
         "contact_person_in_museum_explica": "If this switch is set to yes, the user's name and mail address (and, if the profile is set visible within musdb) will appear in the navigation as a contact for colleagues asking for help.",
         "no_email_set": "No email address has been entered",
-        "user_address_on_blocked_domain": "The user address is hosted by a blocked mail hoster:"
+        "user_address_on_blocked_domain": "The user address is hosted by a blocked mail hoster:",
+        "mail_invalid_domain": "The entered email addresses' domain seems to be invalid."
     }
 }
\ No newline at end of file
diff --git a/backend/en/user.json b/backend/en/user.json
index 3f3af45f..011747eb 100644
--- a/backend/en/user.json
+++ b/backend/en/user.json
@@ -135,6 +135,7 @@
         "contact_persons_in_museum": "Contact persons in museum",
         "contact_person_in_museum_explica": "If this switch is set to yes, the user's name and mail address (and, if the profile is set visible within musdb) will appear in the navigation as a contact for colleagues asking for help.",
         "no_email_set": "No email address has been entered",
-        "user_address_on_blocked_domain": "The user address is hosted by a blocked mail hoster:"
+        "user_address_on_blocked_domain": "The user address is hosted by a blocked mail hoster:",
+        "mail_invalid_domain": "The entered email addresses' domain seems to be invalid."
     }
 }
\ No newline at end of file
diff --git a/backend/es/user.json b/backend/es/user.json
index c3c08303..bdcc4a41 100644
--- a/backend/es/user.json
+++ b/backend/es/user.json
@@ -135,6 +135,7 @@
         "contact_persons_in_museum": "Contact persons in museum",
         "contact_person_in_museum_explica": "If this switch is set to yes, the user's name and mail address (and, if the profile is set visible within musdb) will appear in the navigation as a contact for colleagues asking for help.",
         "no_email_set": "No email address has been entered",
-        "user_address_on_blocked_domain": "The user address is hosted by a blocked mail hoster:"
+        "user_address_on_blocked_domain": "The user address is hosted by a blocked mail hoster:",
+        "mail_invalid_domain": "The entered email addresses' domain seems to be invalid."
     }
 }
\ No newline at end of file
diff --git a/backend/fr/user.json b/backend/fr/user.json
index 52a8379d..2e37cca7 100644
--- a/backend/fr/user.json
+++ b/backend/fr/user.json
@@ -135,6 +135,7 @@
         "contact_persons_in_museum": "Contact persons in museum",
         "contact_person_in_museum_explica": "If this switch is set to yes, the user's name and mail address (and, if the profile is set visible within musdb) will appear in the navigation as a contact for colleagues asking for help.",
         "no_email_set": "No email address has been entered",
-        "user_address_on_blocked_domain": "The user address is hosted by a blocked mail hoster:"
+        "user_address_on_blocked_domain": "The user address is hosted by a blocked mail hoster:",
+        "mail_invalid_domain": "The entered email addresses' domain seems to be invalid."
     }
 }
\ No newline at end of file
diff --git a/backend/hsb/user.json b/backend/hsb/user.json
index 2053beed..24e607ea 100644
--- a/backend/hsb/user.json
+++ b/backend/hsb/user.json
@@ -135,6 +135,7 @@
         "contact_persons_in_museum": "Contact persons in museum",
         "contact_person_in_museum_explica": "If this switch is set to yes, the user's name and mail address (and, if the profile is set visible within musdb) will appear in the navigation as a contact for colleagues asking for help.",
         "no_email_set": "No email address has been entered",
-        "user_address_on_blocked_domain": "The user address is hosted by a blocked mail hoster:"
+        "user_address_on_blocked_domain": "The user address is hosted by a blocked mail hoster:",
+        "mail_invalid_domain": "The entered email addresses' domain seems to be invalid."
     }
 }
\ No newline at end of file
diff --git a/backend/hu/user.json b/backend/hu/user.json
index bbf26432..902fcf4c 100644
--- a/backend/hu/user.json
+++ b/backend/hu/user.json
@@ -135,6 +135,7 @@
         "contact_persons_in_museum": "Kapcsoalttart\u00f3k a m\u00fazeumban",
         "contact_person_in_museum_explica": "A kapcsol\u00f3 aktiv\u00e1l\u00e1s\u00e1val a felhaszn\u00e1l\u00f3 neve \u00e9s email c\u00edme megjelenik a seg\u00edts\u00e9get k\u00e9r\u0151 koll\u00e9g\u00e1knak n\u00e9vjegyek\u00e9nt.",
         "no_email_set": "No email address has been entered",
-        "user_address_on_blocked_domain": "The user address is hosted by a blocked mail hoster:"
+        "user_address_on_blocked_domain": "The user address is hosted by a blocked mail hoster:",
+        "mail_invalid_domain": "The entered email addresses' domain seems to be invalid."
     }
 }
\ No newline at end of file
diff --git a/backend/id/user.json b/backend/id/user.json
index 1a5bf4c4..36c171d0 100644
--- a/backend/id/user.json
+++ b/backend/id/user.json
@@ -135,6 +135,7 @@
         "contact_persons_in_museum": "Contact persons in museum",
         "contact_person_in_museum_explica": "If this switch is set to yes, the user's name and mail address (and, if the profile is set visible within musdb) will appear in the navigation as a contact for colleagues asking for help.",
         "no_email_set": "No email address has been entered",
-        "user_address_on_blocked_domain": "The user address is hosted by a blocked mail hoster:"
+        "user_address_on_blocked_domain": "The user address is hosted by a blocked mail hoster:",
+        "mail_invalid_domain": "The entered email addresses' domain seems to be invalid."
     }
 }
\ No newline at end of file
diff --git a/backend/it/user.json b/backend/it/user.json
index c3c08303..bdcc4a41 100644
--- a/backend/it/user.json
+++ b/backend/it/user.json
@@ -135,6 +135,7 @@
         "contact_persons_in_museum": "Contact persons in museum",
         "contact_person_in_museum_explica": "If this switch is set to yes, the user's name and mail address (and, if the profile is set visible within musdb) will appear in the navigation as a contact for colleagues asking for help.",
         "no_email_set": "No email address has been entered",
-        "user_address_on_blocked_domain": "The user address is hosted by a blocked mail hoster:"
+        "user_address_on_blocked_domain": "The user address is hosted by a blocked mail hoster:",
+        "mail_invalid_domain": "The entered email addresses' domain seems to be invalid."
     }
 }
\ No newline at end of file
diff --git a/backend/iw/user.json b/backend/iw/user.json
index 52a8379d..2e37cca7 100644
--- a/backend/iw/user.json
+++ b/backend/iw/user.json
@@ -135,6 +135,7 @@
         "contact_persons_in_museum": "Contact persons in museum",
         "contact_person_in_museum_explica": "If this switch is set to yes, the user's name and mail address (and, if the profile is set visible within musdb) will appear in the navigation as a contact for colleagues asking for help.",
         "no_email_set": "No email address has been entered",
-        "user_address_on_blocked_domain": "The user address is hosted by a blocked mail hoster:"
+        "user_address_on_blocked_domain": "The user address is hosted by a blocked mail hoster:",
+        "mail_invalid_domain": "The entered email addresses' domain seems to be invalid."
     }
 }
\ No newline at end of file
diff --git a/backend/nl/user.json b/backend/nl/user.json
index c3c08303..bdcc4a41 100644
--- a/backend/nl/user.json
+++ b/backend/nl/user.json
@@ -135,6 +135,7 @@
         "contact_persons_in_museum": "Contact persons in museum",
         "contact_person_in_museum_explica": "If this switch is set to yes, the user's name and mail address (and, if the profile is set visible within musdb) will appear in the navigation as a contact for colleagues asking for help.",
         "no_email_set": "No email address has been entered",
-        "user_address_on_blocked_domain": "The user address is hosted by a blocked mail hoster:"
+        "user_address_on_blocked_domain": "The user address is hosted by a blocked mail hoster:",
+        "mail_invalid_domain": "The entered email addresses' domain seems to be invalid."
     }
 }
\ No newline at end of file
diff --git a/backend/pl/user.json b/backend/pl/user.json
index b9f8c7ac..19cc3c76 100644
--- a/backend/pl/user.json
+++ b/backend/pl/user.json
@@ -135,6 +135,7 @@
         "contact_persons_in_museum": "Contact persons in museum",
         "contact_person_in_museum_explica": "If this switch is set to yes, the user's name and mail address (and, if the profile is set visible within musdb) will appear in the navigation as a contact for colleagues asking for help.",
         "no_email_set": "No email address has been entered",
-        "user_address_on_blocked_domain": "The user address is hosted by a blocked mail hoster:"
+        "user_address_on_blocked_domain": "The user address is hosted by a blocked mail hoster:",
+        "mail_invalid_domain": "The entered email addresses' domain seems to be invalid."
     }
 }
\ No newline at end of file
diff --git a/backend/pt/user.json b/backend/pt/user.json
index 32f2d309..33352b58 100644
--- a/backend/pt/user.json
+++ b/backend/pt/user.json
@@ -135,6 +135,7 @@
         "contact_persons_in_museum": "Contact persons in museum",
         "contact_person_in_museum_explica": "If this switch is set to yes, the user's name and mail address (and, if the profile is set visible within musdb) will appear in the navigation as a contact for colleagues asking for help.",
         "no_email_set": "No email address has been entered",
-        "user_address_on_blocked_domain": "The user address is hosted by a blocked mail hoster:"
+        "user_address_on_blocked_domain": "The user address is hosted by a blocked mail hoster:",
+        "mail_invalid_domain": "The entered email addresses' domain seems to be invalid."
     }
 }
\ No newline at end of file
diff --git a/backend/ru/user.json b/backend/ru/user.json
index f24359c6..e255ec19 100644
--- a/backend/ru/user.json
+++ b/backend/ru/user.json
@@ -135,6 +135,7 @@
         "contact_persons_in_museum": "Contact persons in museum",
         "contact_person_in_museum_explica": "If this switch is set to yes, the user's name and mail address (and, if the profile is set visible within musdb) will appear in the navigation as a contact for colleagues asking for help.",
         "no_email_set": "No email address has been entered",
-        "user_address_on_blocked_domain": "The user address is hosted by a blocked mail hoster:"
+        "user_address_on_blocked_domain": "The user address is hosted by a blocked mail hoster:",
+        "mail_invalid_domain": "The entered email addresses' domain seems to be invalid."
     }
 }
\ No newline at end of file
diff --git a/backend/tl/user.json b/backend/tl/user.json
index c3c08303..bdcc4a41 100644
--- a/backend/tl/user.json
+++ b/backend/tl/user.json
@@ -135,6 +135,7 @@
         "contact_persons_in_museum": "Contact persons in museum",
         "contact_person_in_museum_explica": "If this switch is set to yes, the user's name and mail address (and, if the profile is set visible within musdb) will appear in the navigation as a contact for colleagues asking for help.",
         "no_email_set": "No email address has been entered",
-        "user_address_on_blocked_domain": "The user address is hosted by a blocked mail hoster:"
+        "user_address_on_blocked_domain": "The user address is hosted by a blocked mail hoster:",
+        "mail_invalid_domain": "The entered email addresses' domain seems to be invalid."
     }
 }
\ No newline at end of file
diff --git a/backend/tr/user.json b/backend/tr/user.json
index 085b55c9..a9c92255 100644
--- a/backend/tr/user.json
+++ b/backend/tr/user.json
@@ -135,6 +135,7 @@
         "contact_persons_in_museum": "Contact persons in museum",
         "contact_person_in_museum_explica": "If this switch is set to yes, the user's name and mail address (and, if the profile is set visible within musdb) will appear in the navigation as a contact for colleagues asking for help.",
         "no_email_set": "No email address has been entered",
-        "user_address_on_blocked_domain": "The user address is hosted by a blocked mail hoster:"
+        "user_address_on_blocked_domain": "The user address is hosted by a blocked mail hoster:",
+        "mail_invalid_domain": "The entered email addresses' domain seems to be invalid."
     }
 }
\ No newline at end of file
diff --git a/backend/zh/user.json b/backend/zh/user.json
index 9ff2ac42..ce28271e 100644
--- a/backend/zh/user.json
+++ b/backend/zh/user.json
@@ -135,6 +135,7 @@
         "contact_persons_in_museum": "Contact persons in museum",
         "contact_person_in_museum_explica": "If this switch is set to yes, the user's name and mail address (and, if the profile is set visible within musdb) will appear in the navigation as a contact for colleagues asking for help.",
         "no_email_set": "No email address has been entered",
-        "user_address_on_blocked_domain": "The user address is hosted by a blocked mail hoster:"
+        "user_address_on_blocked_domain": "The user address is hosted by a blocked mail hoster:",
+        "mail_invalid_domain": "The entered email addresses' domain seems to be invalid."
     }
 }
\ No newline at end of file