I solved this same error by taking the Certificate value directly from the metadata file exported from OpenAM and entering that directly again, to ensure that it was the exact same.
I solved this same error by taking the Certificate value directly from the metadata file exported from OpenAM and entering that directly again, to ensure that it was the exact same.
The issue was with the configuration in the Access Management on the token encryption. It was blank but for some reason the JWT header showed HS256, that was caused spring to look for the HS256 private key and fail. After I changed the setting to use RS256, everything started working.