seems we have to add DT3 and mail in iCloud service
Please clarify what you’re referring to here.
not sure it was useful but I activated DT3 and mail in iCloud setup (syst pref / my identifier/ icloud
sorry I use FR version no idea how it is translated in EN.
After this it worked, but not sure at all, and it is not adequate for me to activate mail and DT3 in icloud only to use mail plugin.
Like I wrote it, it now works after restarting. So I will disactivate mail and DT3 in icloud to see if it has any influence
It might be helpful to describe exactly how you tried importing mail into DT.
Unrelated to Mail: DEVONthink should be enabled in System Preferences > Apple ID > iCloud > iCloud Drive: Options in order for it to sync via iCloud Legacy or CloudKit.