If openid-configuration does not contain request_parameter_supported (which is an optional value, see [1]) a NullPointerException is thrown in OidcClientConfiguration.resolveUrls.

Wildfly/Elytron just logs "Unable to load OpenID provider metadata from XXX" and no further information is shown.

We have analyzed this issue and the cause is that OidcProviderMetadata#requestParameterSupported is of type Boolean but in OidcClientConfiguration.resolveUrls it is cast without null check to boolean:

[1]https://openid.net/specs/openid-connect-discovery-1_0.html

This happens with the AWS Cognito OpenID provider.