I had a working solution that has been in service for 1+ years. On 4/8/2022, the certificate expired, and I got a new certificate from my Service Desk group. I re-uploaded the certificate to my Azure App Service, and then realized I needed to re-deploy the code with the new Thumbprint. I am uploading to the TLS/SSL settings Private Key Certificates (.pfx).
I re-deployed along with some debugging log lines, and it seems that StoreName.My + StoreLocation.CurrentUser has 0 certificates currently in the store. This is pre any thumbprint filtering.
As I said, this has been working for the last 1-2 years, but the new certificate is now causing it to fail. I attempted to look at a couple other stores, they had certificates in them, but none of them had my Thumbprint. [40 in Root,CurrentUser] [9 in My,LocalMachine].
I am using a code equivalent to the example here: https://learn.microsoft.com/en-us/azure/app-service/configure-ssl-certificate-in-code
Edit: noteworthy, this all works fine on my local computer.