Information
The signatureAlgorithm is used by the OP to sign the ID tokens.
The OpenID Connect Server Provider should use a signature algorithm to sign the ID tokens. This protects sensitive information and helps the relying party verify the authenticity of the JWT.
Solution
Add the signatureAlgorithm attribute to the openidConnectProvider element to ${server.config.dir}/configDropins/overrides/*.xml and set it to a valid algorithm, such as RS256 to ensure tokens are signed.
<openidConnectProvider signatureAlgorithm="RS256" />