diff --git a/api/management/api.go b/api/management/api.go
index fe7ec0633..53750b472 100644
--- a/api/management/api.go
+++ b/api/management/api.go
@@ -284,7 +284,7 @@ func (password PasswordRepresentation) Validate() error {
 }
 
 func (config RealmCustomConfiguration) Validate() error {
-	if config.DefaultClientId != nil && !matchesRegExp(*config.DefaultClientId, RegExpID) {
+	if config.DefaultClientId != nil && !matchesRegExp(*config.DefaultClientId, RegExpClientID) {
 		return errors.New("Invalid default client ID")
 	}
 
diff --git a/api/management/api_test.go b/api/management/api_test.go
index bcab14ad4..ad0791561 100644
--- a/api/management/api_test.go
+++ b/api/management/api_test.go
@@ -188,7 +188,7 @@ func TestValidateRealmCustomConfiguration(t *testing.T) {
 		assert.Nil(t, config.Validate())
 	}
 
-	defaultClientID := "f467ed7c"
+	defaultClientID := "something$invalid"
 	defaultRedirectURI := "ht//tp://company.com"
 
 	var configs []RealmCustomConfiguration
@@ -276,7 +276,7 @@ func createValidPasswordRepresentation() PasswordRepresentation {
 }
 
 func createValidRealmCustomConfiguration() RealmCustomConfiguration {
-	defaultClientID := "f467ed7c-0a1d-4eee-9bb8-669c6f89c0ee"
+	defaultClientID := "backofficeid"
 	defaultRedirectURI := "http://company.com"
 
 	return RealmCustomConfiguration{