Excalidraw installation fails

What app is this about, and its version: Excalidraw (latest)
What YunoHost version are you running: 12.1.40.1 (stable)
What type of hardware are you using: VPS bought online

Describe your issue

Same issue as this (closed): Excalidraw installation-script fails
That was solved by installing via ssh, but I do not know hopw to do that (correctly).

Translated from Danish I get this error message:

Error: “502”

Handling: “POST” /yunohost/api/apps

The Yunohost API does not respond. Perhaps ‘yunohost-api’ is down or has been restarted?

The last line in the reposnses from the server says:

“Building app… (this will take some time and resources!)”

Share relevant logs or error messages

It requires much ram and disk space to install.

You can try yunohost app install excalidraw

Perhaps this is the problem? Anyway, it is not very important to me - just fun (so I will probably let it be for now).

Thanks