Collaboration unavailable

This has worked before, but is now failing. Attempting to share a note with other iPhone users but now I receive an error with states collaboration is unavailable, unable to start collaboration.

The notes are stored in iCloud.

I have plenty of space on my phone and in iCloud as does the target user.

Both I and the target user are on the latest version of iOS.

Both I and the target user are using iMessage.

I have turned off note syncing and iCloud and then turned it back on.

I’ve performed a hard reboot of the phone.

Any further suggestions before I reach out to Apple support?