[auth][cause]: OperationProcessingError: "response" is not a conform Token Endpoint response with Keycloak and NextJS

[idc77]

[auth][error] CallbackRouteError: Read more at https://errors.authjs.dev#callbackrouteerror
[auth][cause]: OperationProcessingError: "response" is not a conform Token Endpoint response
    at OPE (webpack-internal:///(rsc)/./node_modules/.pnpm/[email protected]/node_modules/oauth4webapi/build/index.js:179:12)
    at processGenericAccessTokenResponse (webpack-internal:///(rsc)/./node_modules/.pnpm/[email protected]/node_modules/oauth4webapi/build/index.js:1213:15)
    at process.processTicksAndRejections (node:internal/process/task_queues:105:5)
    at async processAuthorizationCodeOpenIDResponse (webpack-internal:///(rsc)/./node_modules/.pnpm/[email protected]/node_modules/oauth4webapi/build/index.js:1419:20)
[auth][details]: {
  "provider": "keycloak"
}
[auth][error] UnknownAction: Cannot parse action at /api/auth/installHook.js.map. Read more at https://errors.authjs.dev#unknownaction
    at parseActionAndProviderId (webpack-internal:///(rsc)/./node_modules/.pnpm/@[email protected]/node_modules/@auth/core/lib/utils/web.js:113:15)
    at toInternalRequest (webpack-internal:///(rsc)/./node_modules/.pnpm/@[email protected]/node_modules/@auth/core/lib/utils/web.js:37:40)
    at Auth (webpack-internal:///(rsc)/./node_modules/.pnpm/@[email protected]/node_modules/@auth/core/index.js:87:103)
    at httpHandler (webpack-internal:///(rsc)/./node_modules/.pnpm/[email protected][email protected][email protected][email protected][email protected][email protected]/node_modules/next-auth/index.js:142:82)
    at /home/darko/WebstormProjects/nextjs/cooksbooks/node_modules/.pnpm/[email protected][email protected][email protected][email protected]/node_modules/next/dist/compiled/next-server/app-route.runtime.dev.js:6:63815
    at /home/darko/WebstormProjects/nextjs/cooksbooks/node_modules/.pnpm/[email protected][email protected][email protected][email protected]/node_modules/next/dist/server/lib/trace/tracer.js:133:36
    at NoopContextManager.with (/home/darko/WebstormProjects/nextjs/cooksbooks/node_modules/.pnpm/[email protected][email protected][email protected][email protected]/node_modules/next/dist/compiled/@opentelemetry/api/index.js:1:7062)
    at ContextAPI.with (/home/darko/WebstormProjects/nextjs/cooksbooks/node_modules/.pnpm/[email protected][email protected][email protected][email protected]/node_modules/next/dist/compiled/@opentelemetry/api/index.js:1:518)
    at NoopTracer.startActiveSpan (/home/darko/WebstormProjects/nextjs/cooksbooks/node_modules/.pnpm/[email protected][email protected][email protected][email protected]/node_modules/next/dist/compiled/@opentelemetry/api/index.js:1:18093)
    at ProxyTracer.startActiveSpan (/home/darko/WebstormProjects/nextjs/cooksbooks/node_modules/.pnpm/[email protected][email protected][email protected][email protected]/node_modules/next/dist/compiled/@opentelemetry/api/index.js:1:18854)
    at /home/darko/WebstormProjects/nextjs/cooksbooks/node_modules/.pnpm/[email protected][email protected][email protected][email protected]/node_modules/next/dist/server/lib/trace/tracer.js:122:103
    at NoopContextManager.with (/home/darko/WebstormProjects/nextjs/cooksbooks/node_modules/.pnpm/[email protected][email protected][email protected][email protected]/node_modules/next/dist/compiled/@opentelemetry/api/index.js:1:7062)
    at ContextAPI.with (/home/darko/WebstormProjects/nextjs/cooksbooks/node_modules/.pnpm/[email protected][email protected][email protected][email protected]/node_modules/next/dist/compiled/@opentelemetry/api/index.js:1:518)
    at NextTracerImpl.trace (/home/darko/WebstormProjects/nextjs/cooksbooks/node_modules/.pnpm/[email protected][email protected][email protected][email protected]/node_modules/next/dist/server/lib/trace/tracer.js:122:28)
    at /home/darko/WebstormProjects/nextjs/cooksbooks/node_modules/.pnpm/[email protected][email protected][email protected][email protected]/node_modules/next/dist/compiled/next-server/app-route.runtime.dev.js:6:56866
    at AsyncLocalStorage.run (node:internal/async_local_storage/async_hooks:91:14)
    at Object.wrap (/home/darko/WebstormProjects/nextjs/cooksbooks/node_modules/.pnpm/[email protected][email protected][email protected][email protected]/node_modules/next/dist/compiled/next-server/app-route.runtime.dev.js:6:37102)
    at /home/darko/WebstormProjects/nextjs/cooksbooks/node_modules/.pnpm/[email protected][email protected][email protected][email protected]/node_modules/next/dist/compiled/next-server/app-route.runtime.dev.js:6:54639
    at AsyncLocalStorage.run (node:internal/async_local_storage/async_hooks:91:14)
    at Object.wrap (/home/darko/WebstormProjects/nextjs/cooksbooks/node_modules/.pnpm/[email protected][email protected][email protected][email protected]/node_modules/next/dist/compiled/next-server/app-route.runtime.dev.js:6:36351)
    at /home/darko/WebstormProjects/nextjs/cooksbooks/node_modules/.pnpm/[email protected][email protected][email protected][email protected]/node_modules/next/dist/compiled/next-server/app-route.runtime.dev.js:6:54601
    at AsyncLocalStorage.run (node:internal/async_local_storage/async_hooks:91:14)
    at eU.execute (/home/darko/WebstormProjects/nextjs/cooksbooks/node_modules/.pnpm/[email protected][email protected][email protected][email protected]/node_modules/next/dist/compiled/next-server/app-route.runtime.dev.js:6:53994)
    at eU.handle (/home/darko/WebstormProjects/nextjs/cooksbooks/node_modules/.pnpm/[email protected][email protected][email protected][email protected]/node_modules/next/dist/compiled/next-server/app-route.runtime.dev.js:6:65073)
    at doRender (/home/darko/WebstormProjects/nextjs/cooksbooks/node_modules/.pnpm/[email protected][email protected][email protected][email protected]/node_modules/next/dist/server/base-server.js:1315:60)
    at cacheEntry.responseCache.get.routeKind (/home/darko/WebstormProjects/nextjs/cooksbooks/node_modules/.pnpm/[email protected][email protected][email protected][email protected]/node_modules/next/dist/server/base-server.js:1525:46)
    at ResponseCache.get (/home/darko/WebstormProjects/nextjs/cooksbooks/node_modules/.pnpm/[email protected][email protected][email protected][email protected]/node_modules/next/dist/server/response-cache/index.js:49:26)
    at DevServer.renderToResponseWithComponentsImpl (/home/darko/WebstormProjects/nextjs/cooksbooks/node_modules/.pnpm/[email protected][email protected][email protected][email protected]/node_modules/next/dist/server/base-server.js:1445:53)

AUTH_SECRET="removed" # Added by `npx auth`. Read more: https://cli.authjs.dev
AUTH_KEYCLOAK_ID=next-auth
AUTH_KEYCLOAK_SECRET=removed
AUTH_KEYCLOAK_ISSUER=https://domain.tld/auth/realms/realmname

How can I debug what is happening?
How can I see the response?

update:
It's some kind of issue with Keycloak 26.0.5

I tried Zitadel and it's working.
But still I don't know how to debug this, even with debug enabled, it gives me nothing useful.
I'd like to inspect the response returned from Keycloak.
How?

[panva]

I'd like to inspect the response returned from Keycloak. How?

The OperationProcessingError instance has a cause property which in this case would be the Response instance (assuming you're using a next-auth version dependent on [email protected].