I was asked to update the SSL certificates on a website that was hosted in Azure Web Apps. No problem I thought.
Go to the Azure Portal,
Select the website you want to update.
When the blade appears scroll down the left panel and select SSL Certificates
remove the binding, by clicking … at the end of the binding row and select Delete
Now remove the certificate by clicking .. at the end of the certificate row and select Delete
This is where I got an error
It took a short while to resolve this.
I tried a few things like restarting the site & checking the staging slot, but I still got the error. Finally, I checked other sites in the same app service plan and I had the same certificate used for another Web App (both using the same domain url). Once I removed the binding from that site, I could delete the certificate and upload a new one. I had to then add the new bindings to both sites.