diff --git a/resources/js/event_billing.js b/resources/js/event_billing.js
index da5cb9a..d71df32 100644
--- a/resources/js/event_billing.js
+++ b/resources/js/event_billing.js
@@ -105,6 +105,9 @@ EventBilling = (function () {
                 alert("Es ist ein Fehler aufgetreten!");
             }
         });
+        if(typeof res !== 'object'){
+            return res;
+        }
         if('error' in res){
             return null;
         }else{
@@ -196,16 +199,14 @@ EventBilling = (function () {
             } else if (event.state === 6) {
                 $(".goto_personnel_billing").show();
             } else if (event.state >= 7) {
-                let min_billing_state;
-                if (!event_min_billing_state.error) {
-                    min_billing_state = event_min_billing_state;
-                } else {
-                    min_billing_state = billing_states[0].entity_id;
+                if (!event_min_billing_state) {
+                    $(".goto_approve_" + billing_states[0].entity_id).show();
                 }
+
                 //Show next approval step (billing_state) button
                 for (let i = 0; i < billing_states.length - 1; i++) {
-                    if (billing_states[i].entity_id === min_billing_state) {
-                        $(".goto_approve_" + billing_states[i + 1].entity_id).show();
+                    if (billing_states[i].entity_id === event_min_billing_state) {
+                        $(".goto_approve_" + billing_states[i+1].entity_id).show();
                     }
                 }
             }