Homepage not working anymore on google cloud

What does this mean when accessing a website? I cannot anymore show my website for a reason unknown to me. Could it relate to SSL certificate to be renewed? The website still shows the small icon image but not the main content. The website was on Google Cloud platform. I am beginner, but I thought I can at least google the problem but no, nothing seems to help. So what does this refer to, please help:

{ "kind": "Status", "apiVersion": "v1", "metadata": {

}, "status": "Failure", "message": "forbidden: User \"system:anonymous\" cannot get path \"/\"", "reason": "Forbidden", "details": {

}, "code": 403 }

{ "kind": "Status", "apiVersion": "v1", "metadata": {

}, "status": "Failure", "message": "forbidden: User \"system:anonymous\" cannot get path \"/\"", "reason": "Forbidden", "details": {

}, "code": 403 }