diff --git a/internal/service/default.go b/internal/service/default.go
index 9810fba..b1ada14 100644
--- a/internal/service/default.go
+++ b/internal/service/default.go
@@ -10,7 +10,7 @@ const (
 )
 
 var (
-	safeInputRegex = regexp.MustCompile(`^[a-zA-Z0-9ÄÖÜäöüß,&'". -]+$`)
+	safeInputRegex = regexp.MustCompile(`^[a-zA-Z0-9ÄÖÜäöüß,&'". \-\?]+$`)
 )
 
 func validateString(value string, fieldName string) error {
diff --git a/test/main_it_test.go b/test/main_it_test.go
index d3dc186..c4a6b50 100644
--- a/test/main_it_test.go
+++ b/test/main_it_test.go
@@ -1862,7 +1862,6 @@ func TestIntegrationAccount(t *testing.T) {
 				">":       400,
 				"/":       400,
 				"\\":      400,
-				"?":       400,
 				":":       400,
 				"*":       400,
 				"|":       400,