Password change for synchronization not sticking

This is for OmniFocus on macOS.

I’ve changed the password on the sync server and entered it into my two Macs and my iPhone. After doing that, synchronization works perfectly. However, on one of my Macs the old password is used every time I start the application, so I’m forced to enter the new password. Perhaps the fix is as simple as deleting some items from my keychain, but there are more OmniFocus-related items there than expected. (Maybe a bunch are obsolete.)

Any ideas on how to fix this?