NPMplus: Failed to Login

After some time docker running I can no more log in to my NGINXPROXYMANAGER: I have to manaually docker restart nginxproxymanager. Here are server logs:

2023/07/26 17:55:42 [error] 11102#11102: *332 connect() failed (111: Connection refused) while connecting to upstream, client: 127.0.0.1, server: _, request: "POST /api/tokens HTTP/1.1", upstream: "http://127.0.0.1:48693/tokens", host: "proxy.afzal.website", referrer: "https://proxy.afzal.website/login"
2023/07/26 17:56:07 [error] 11069#11069: *334 connect() failed (111: Connection refused) while connecting to upstream, client: 127.0.0.1, server: _, request: "GET /api/ HTTP/2.0", upstream: "http://127.0.0.1:48693/", host: "localhost:81"
2023/07/26 17:56:08 [error] 11135#11135: *351 connect() failed (111: Connection refused) while connecting to upstream, client: 127.0.0.1, server: _, request: "GET /api/ HTTP/1.1", upstream: "http://127.0.0.1:48693/", host: "proxy.afzal.website", referrer: "https://proxy.afzal.website/"
2023/07/26 17:56:23 [error] 11135#11135: *366 connect() failed (111: Connection refused) while connecting to upstream, client: 127.0.0.1, server: _, request: "POST /api/tokens HTTP/1.1", upstream: "http://127.0.0.1:48693/tokens", host: "proxy.afzal.website", referrer: "https://proxy.afzal.website/login"
2023/07/26 17:56:37 [error] 11069#11069: *368 connect() failed (111: Connection refused) while connecting to upstream, client: 127.0.0.1, server: _, request: "GET /api/ HTTP/2.0", upstream: "http://127.0.0.1:48693/", host: "localhost:81"