Cannot get Super Productivity (SP) to sync with Apple Calendar

[Grumpster-Dev]

Just downloaded SP this morning. Looks very promising, but I need it to integrate into the MacOS (15.3) ecosystem.

I tried the 'Connect Calendar' sidebar choosing 'iCal' as the calendar. It asks for a URL. Logged into iCloud.com Went to Calendar, selected the user I wanted to sync. Selected the share calendar icon, and copied the url of the 'Public Calendar', and pasted that into the 'Url of iCal source' field in SP. No joy - when I clicked test at bottom it returned "Connection failed".

Then I tried sharing that Calendar with an alias of mine...copied that incoming link - which was a completely different URL, pasted into SP iCal url field as before, and clicked Test and got an 'it works!' pop up. That was encouraging...until seeing the message:

"Calendar provider error. cannot read the properties param" or something along those lines .. Not an exact quote.

Am at a total loss here. This is a Mac app distro, so I expect it is possible to connect these two, but I do not see how.

Thoughts and suggestions are most welcome!!

PS - this app situation got me to register on Github!

Cheers