diff -r 785820da6485 -r c9c6abf167c7 src/main/resources/localization/strings.properties
--- a/src/main/resources/localization/strings.properties	Tue Aug 03 12:22:10 2021 +0200
+++ b/src/main/resources/localization/strings.properties	Tue Aug 03 13:41:32 2021 +0200
@@ -128,6 +128,7 @@
 user.lastname=Last Name
 user.mail=E-Mail
 username=User Name
+validation.username.null=Username is mandatory.
 validation.username.unique=Username is already taken.
 version.latest=Latest Version
 version.next=Next Version