bon j'ai arrêté d'utiliser un secret et j'ai mis le certificat directement dans la configuration d'Authelia et c'est OK.
enfin, "ok", ... je suis à l'erreur suivante.
komga | org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'securityConfiguration' defined in file [/app/BOOT-INF/classes/org/gotson/komga/infrastructure/security/SecurityConfiguration.class]: Unsatisfied dependency expressed through constructor parameter 7; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'clientRegistrationRepository' defined in class path resource [org/springframework/boot/autoconfigure/security/oauth2/client/servlet/OAuth2ClientRegistrationRepositoryConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.security.oauth2.client.registration.InMemoryClientRegistrationRepository]: Factory method 'clientRegistrationRepository' threw exception; nested exception is java.lang.IllegalArgumentException: Unable to resolve Configuration with the provided Issuer of "< là il met bien l'URL d'Authelia" >