Oh great - and sorry, I should have read the thread a little more closely.
Tried to install on MacOS but I can’t login.
When I start the app, I get two windows. One is a new chrome window which asks me to login and me give permissions. When I login, I leave the permissions and default and click OK. I get a small popup to open the “intervals companion app” and click OPEN. Now the second window comes to the front which says “logging in…” and it stays at this forever.
When I close the first window (chrome), The second window immediately gives an error “Permission required, unable to login”.
Interesting. Logging in initially via macOS is untested functionality. If you login first from an iPad or iPhone that uses the same iCloud account, and iCloud keychain syncing is enabled, it should store your credentials securely in the keychain and start working in macOS.
I’m interested to know if changing your default browser temporarily to safari would help. I’m pretty sure the login needs to happen in an embedded browser window within the app for the login handshake to work.
Very nice companion app.
What I dont’t understand however (but I did not look into detail yet): my fitness numbers are completely different then those in intervals.icu itself…
If you go to the settings in the app what is the Form Display set as? I believe it defaults to ‘percent of fitness’, which may not match your setting on intervals.icu which I think defaults to the absolute number.
I thought about keeping the app setting in sync with the user setting, but I also like the easy ability to change it back and forth in the app.
It’s perfect like this, it confirmed my feeling of being tired → in the ‘risk’ zone 
While based on the absolute values; everything is ‘optimal’.
But as such it might be giving different interpretations.
In any case, load / TSS is limited anyway…