404 on every page

[merimus]

$ python3 app.py
INFO: Started server process [111294]
INFO: Waiting for application startup.
INFO: Application startup complete.
INFO: Uvicorn running on http://127.0.0.1:7437 (Press CTRL+C to quit)
INFO: 127.0.0.1:48890 - "GET /api/provider HTTP/1.1" 200 OK

$ yarn dev
Messages
yarn dev
yarn run v1.22.19
$ next dev
ready - started server on 0.0.0.0:3000, url: http://localhost:3000
info - Loaded env from /home/merimus/Agent-LLM-Frontend/.env.local
info - Disabled SWC as replacement for Babel because of custom Babel configuration ".babelrc" https://nextjs.org/docs/messages/swc-disabled
event - compiled client and server successfully in 7.5s (11823 modules)
wait - compiling /provider (client and server)...
event - compiled client and server successfully in 2.1s (12008 modules)
wait - compiling /_error (client and server)...
event - compiled client and server successfully in 1872 ms (12009 modules)
Promise { }
warn - Fast Refresh had to perform a full reload. Read more: https://nextjs.org/docs/messages/fast-refresh-reload
Promise { }
{
mutate: [Function (anonymous)],
data: [Getter],
error: [Getter],
isValidating: [Getter],
isLoading: [Getter]
}

all web pages show Error!
Request failed with status code 404

Any suggestions?