App integrity in Google Play no longer accepting my private key path

I have been using this encrypted_private_key_path for years and all of a sudden I get the error message The private key was not properly encrypted, or is not a type of key we support. Google Support keeps saying it is on my end and to regenerate a new key or something. I don't want to do this since 600 apps use this private key already. Is there anything I can do to verify this or report a bug if there is one?

I have recently faced the same issue, and after investigating hours the solution was to use the latest Open JDK instead.

I guess my situation was the same like yours. There was no any error when generating the private key, but the Play Store showed the error message continuously. I checked the command, the encryption public key and the keystore itself more than 5 times and I exactly did what is in the instruction. And the generated private key was rejected with the same error message.

The last thing what I asked from myself is what if the JDK matters. So, I downloaded the latest Open JDK (in my case 20.0.2) and I executed the exactly same command by using the downloaded Open JDK. And it worked, the Play Store accepted the generated private key. (Usually, I use the Android Studio built-in Java)