auth-ldap: improve messages when users failed to authenticate. Fixes #5345

rhodecode/authentication/plugins/auth_ldap.py

@@ -293,7 +293,8 b' class AuthLdap(object):'
             log.warning(msg, username)
             raise LdapPasswordError(msg)
         if "," in username:
-            raise LdapUsernameError("invalid character in username: ,")
+            raise LdapUsernameError(
+                "invalid character `,` in username: `{}`".format(username))
         try:
             server = self._get_ldap_server()
             filter_ = '(&%s(%s=%s))' % (
@@ -319,8 +320,9 b' class AuthLdap(object):'
                     break
 
             else:
-                raise LdapPasswordError('Failed to authenticate user '
-                                        'with given password')
+                raise LdapPasswordError(
+                    'Failed to authenticate user `{}`'
+                    'with given password'.format(username))
 
         except ldap.NO_SUCH_OBJECT:
             log.debug("LDAP says no such user '%s' (%s), org_exc:",