login_name already exists

Detail: Key (login_name)=(XXXXX) already exists.
Caused by: org.postgresql.util.PSQLException: ERROR: duplicate key value violates unique constraint "uc_users_loginname"

at de.hsrm.sls.subato.auth.KeycloakLoginHandler.handleToken(KeycloakLoginHandler.java:89) ~[classes!/:2.0.0-beta6-SNAPSHOT]
at de.hsrm.sls.subato.auth.KeycloakLoginHandler.updateUserFromToken(KeycloakLoginHandler.java:113) ~[classes!/:2.0.0-beta6-SNAPSHOT]