Power Pages Microsoft Login Failing – Client Assertion Expired After Certificate Renewal

Question

We have our site in Power Pages and certificate-based client authentication is being used. The site was working until certificate expired. We have renewed the certificate but there is no provision to upload PFX and ChatGPT says , In current (modern) Power Pages setup, there is no supported way for you to manually add or switch the client certificate/secret yourself and Microsoft support ticket has been raised but we are not receiving expected support. We need help to understand more on the issue and discuss possible solutions. The recommended approach, suggested by ChatGPT, is Option 1 (Correct & Recommended)

 

Open Microsoft Support and request:

 

Reset Microsoft identity provider binding for Power Pages site to use new certificate or switch to client secret.

 

They will:

 

Clear stored private key

 

Rebind authentication method

 

Fix the backend confidential client configuration

 

This is a backend operation only Microsoft can perform.