ActivityWatch app doesn't start in macOS Big Sur.
localhost:5600 is uavailable
ActivityWatch should started
Without a log or error message this is not very helpful.
Could you try running it from the command line and check the system journal?
➜ ~ open /Applications/ActivityWatch.app
LSOpenURLsWithRole() failed with error 2 for the file /Applications/ActivityWatch.app.
Googling for the particular error code ("LSOpenURLsWithRole() failed with error 2", with quotes) gave no result...
The only somewhat similar results were for the infamous error code -10810, it would be nice if someone could double-check the workarounds in that link because I really have no idea how to make progress on this with the information given.
WARNING:root:Could not import pymongo, not available as a datastore backend
maybe this helps?
PS
how to switch on debug mode?
So you could start it but it crashes? Please provide full logs and by which method you run it (double-clicking the app, running open ActivityWatch.app, running one of the binaries in the ActivityWatch.app folder, etc). That particular warning isn't relevant.
There is no debug mode that would be useful for this particular issue (not without building from source anyway).
I can start it without crash only with command line
open /Applications/ActivityWatch.app/Contents/MacOS/aw-server&
but not the icon
I tried both chmod +x and xattr via link above - nothing worked for me
I wrote above that JOSM doesn't start too but it threws another error
➜ ~ open /Applications/ActivityWatch.app
LSOpenURLsWithRole() failed with error 2 for the file /Applications/ActivityWatch.app.
➜ ~ open /Applications/JOSM.app
LSOpenURLsWithRole() failed with error 1 for the file /Applications/JOSM.app.
If I do this to launch AW,
/Applications/ActivityWatch.app/Contents/MacOS/aw-server
it will work.
@fr-kyleli confirmed
Found an issue with running /Applications/ActivityWatch.app/Contents/MacOS/aw-server
AW doesn't understand host this way:

OK, today I managed to run AW via launchd
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>KeepAlive</key>
<true/>
<key>Label</key>
<string>local.ActivityWatch.keepAlive</string>
<key>ProgramArguments</key>
<array>
<string>/usr/bin/open</string>
<string>-W</string>
<string>/Applications/ActivityWatch.app</string>
</array>
</dict>
</plist>
BUT :)
localhost:5600 says that there are no afk and window watchers :(
EDIT:
fall back to commad line launch:
/Applications/ActivityWatch.app/Content/MacOS/aw-qt&
this way I managed to get afk and window watchers running. Spotify watcher isn't working yet.