Hi @Imre_Fazekas,
Thank you for your post and welcome to the community 
.
It looks like you’re using the OpenID Connect (OIDC) authentication method. Please note that this method is now deprecated, and we recommend using the JWT authentication method instead.
You can find more details on JWT auth in our documentation and also review a similar discussion on the topic.
Let us know how you get on, and feel free to raise any issues you encounter.
Also, please include your Gateway version so we can provide more specific guidance.