Creating dev account fails with: "Error posting observer link to discord"

[SlausB]

Relevant system information

• Ubuntu 22.04, inside Ubuntu 22.04 docker as user with id 1000

What I did

Built and run server, opened localhost:3000 and clicked Login -> Login with Dev -> Create New Account

What went wrong

Server started restarting after printing:

[   web] 09:43:42 ERROR: Error posting join observer link to discord for 339036189528925. TypeError: fetch failed
[   web] 09:43:42     at Object.fetch (node:internal/deps/undici/undici:11576:11)
[   web] 09:43:42     at processTicksAndRejections (node:internal/process/task_queues:95:5)
[   web] 09:43:42     at async jsonPostAnyResponse (webpack-internal:///./src/shared/util/fetch_helpers.ts:139:17)
[   web] 09:43:42     at async Promise.all (index 0)
[   web] 09:43:42     at async postToDiscord (webpack-internal:///./src/server/web/util/discord.ts:65:5)
[   web] 09:43:42     at async postJoinObserverLinkToDiscord (webpack-internal:///./src/server/web/util/discord.ts:102:5) pathname:/auth/dev/callback
[   web] 09:43:42 error: 
[   web] 09:43:42   cause: 
[   web] 09:43:42     errno:   -111
[   web] 09:43:42     code:    ECONNREFUSED
[   web] 09:43:42     syscall: connect
[   web] 09:43:42     address: 127.0.0.1
[   web] 09:43:42     port:    80
[   web] 09:43:42     name:    Error
[   web] 09:43:42     message: connect ECONNREFUSED 127.0.0.1:80
[   web] 09:43:42     stack: 
[   web] 09:43:42       """
[   web] 09:43:42         Error: connect ECONNREFUSED 127.0.0.1:80
[   web] 09:43:42             at TCPConnectWrap.afterConnect [as oncomplete] (node:net:1595:16)
[   web] 09:43:42             at TCPConnectWrap.callbackTrampoline (node:internal/async_hooks:130:17)
[   web] 09:43:42       """

Suggestions

Maybe something must be running on port 80 for server to connect to? What is it?