I used to have permissions to remove a custom domain on Google App Engine or upload a new SSL certificate.
However, one day the SSL certificate was expired and I could not upload a new SSL certificate and got the following warning message.
"You do not have sufficient permissions to view this page".
When I remove this custom domain and also got the following warning message.
"All domains mapped to this application are shown below. Only owners of a domain may remove one of its mappings."
I am the owner of managing the domain name group in Google Cloud DNS and project.
Any ideas to solve this issue.