diff --git a/kubernetes/apps/default/authelia/app/config/configuration.yaml b/kubernetes/apps/default/authelia/app/config/configuration.yaml
index d0a83c54c..61e3936f0 100644
--- a/kubernetes/apps/default/authelia/app/config/configuration.yaml
+++ b/kubernetes/apps/default/authelia/app/config/configuration.yaml
@@ -131,6 +131,7 @@ identity_providers:
         scopes: [openid, profile, email, offline_access]
         redirect_uris: ["https://docs.${SECRET_EXTERNAL_DOMAIN}/auth/oidc.callback"]
         userinfo_signed_response_alg: none
+        token_endpoint_auth_method: client_secret_post
       - client_id: paperless
         client_name: Paperless
         client_secret: "$${PAPERLESS_OAUTH_DIGEST}"
diff --git a/kubernetes/apps/default/outline/app/helmrelease.yaml b/kubernetes/apps/default/outline/app/helmrelease.yaml
index 0f71ff9b3..acc8f6d68 100644
--- a/kubernetes/apps/default/outline/app/helmrelease.yaml
+++ b/kubernetes/apps/default/outline/app/helmrelease.yaml
@@ -64,7 +64,7 @@ spec:
               OIDC_SCOPES: openid profile email offline_access
               OIDC_TOKEN_URI: "https://auth.${SECRET_EXTERNAL_DOMAIN}/api/oidc/token"
               OIDC_USERINFO_URI: "https://auth.${SECRET_EXTERNAL_DOMAIN}/api/oidc/userinfo"
-              OIDC_USERNAME_CLAIM: email
+              OIDC_USERNAME_CLAIM: preferred_username
               PORT: 8080
               REDIS_URL: redis://dragonfly.database.svc.cluster.local.:6379
               SMTP_HOST: smtp-relay.default.svc.cluster.local.