Shared calendar invitation won’t open for invitee

I am still having problems. I tried everything mentioned here already. My boss wants to share his calendar with me, he invited me from the Calendar app on his iPhone and sent to my work email I tried to open and got the annoying spinning square. Then I asked him to send again to my icloud email, he sent multiple times and I never got that on my iCloud mail. So then I read the info here and tried to get the invitation from my inbox inside my calendar app but there is nothing there.

My brother has the same spinning square from the calendar link I shared with him—iCloud calendar is enabled.

I too have an invitee who gets only the spinning square. I invited two people to a calendar. One person accepted with no problem. The other person has only a spinning square.

This solved it for me, thank you!

This worked for me too, thank you!

OP- I believe this response should be marked as "Solved" now because I had to read every response before I realized that someone had posted useful information here.

Chrome worked for me! Safari would only give the spinning box, but Chrome worked perfectly. Shame on you Apple!

Whether I send the invite to me from spouses phone or from me to spouse, we both get the spiny circle and we have never been able to share on the phones we currently have.