There is a support article on this topic here:
But I thought I’d post about it here as well in case anyone has an easier time finding this information here in the forum.
Note: The OmniFocus Reminders calendar is an old feature that we added before other newer features that probably accomplish its goal better. If you’re still using this calendar and want to keep doing so, read on! If not, you may want to simply turn it off all-together.)
➤ Repeating Calendar password prompts on iOS can be caused by two different things (that we’re aware of), sadly neither is controlled by OmniFocus itself. That said, the following actions seem to get the prompts to stop…at least for a while.:
1.) Make sure the calendar is not syncing through iCloud.
2.) Delete the password from Keychain (then manually re-enter).
➤ To address both of those ↑ see below ↓:
1.) To remove the calendar from iCloud, make sure the setting on the Mac is set to “On My Mac” following the steps here:
(Note: After doing that, if you still want the OmniFocus Reminders calendar on your iOS device(s) as well, follow the instructions in this support article for setting that up:
2.) To delete the calendar password from Keychain follow the steps here (make sure you get them all and know the correct password to re-enter!):