unexpected JWT alg received

[molnarti]

I have trouble setting up Authentik as an Audiobookshelf authenticator. In the ABS logs I am getting this error:
ERROR: "[Auth] No data in openid callback - RPError: unexpected JWT alg received, expected RS256, got: HS256"

ABS has a Signing Algorithm setting that is set by default to RS256, however setting it to HS256 did not help,

Any idea what could be the issue here?

[dkowis]

This means you need to configure your application to use a signing key that is an RSA certificate.

That will configure authentik to sign not using the HS256 algorithm (based on the client secret) and instead use the RSA key to do it.