Anvil-app-server, anvil.server.call does not work

What I’m trying to do:
I installed a new Ubuntu server 20.04. LTS. I followed the steps described in anvil-runtime/getting-started.md at master · anvil-works/anvil-runtime · GitHub

I start my server:
anvil-app-server --app MY-APP --origin MY-STATIC-IP
Everything works except for the functions prescribed in the server module. Those that are called in the code as anvil.server.call(FOO)

Here is what the server says:

[TRACE anvil.app-server.run] Invalidating; new version 1
[INFO anvil.core.server] HTTP Server running on port 80
[INFO anvil.app-server.run] App URL: MY-STATIK-IP
[INFO anvil.app-server.dispatch] Launching built-in downlink…
[INFO anvil.app-server.run] SMTP Server running on port 25
Connecting to ws://localhost:80/_/downlink
Anvil websocket open
[INFO anvil.executors.downlink] Downlink client connected with spec {:runtime “python3-full”, :session_id “WfAxGcMkauJLEUPkSuPm”}
Downlink authenticated OK

There are no errors on the server, it only pops up in the browser - “Unhandled runtime error”

If I do the same on a normal local computer. And I run it like this
anvil-app-server --app MY-APP
Calling back-end functions works great.

Please tell me what’s wrong?

In general, when using the URL, not IP, everything worked great.