I just transferred data from an old iPhone (on which Joplin sync worked and continues to work fine), and while the target configuration works, attempting to sync gives the error "No such master key." E2EE is not enabled. I'm not sure why there would be a master key set, or where to find it so I can delete it.
Still haven’t been able to find a solution to this, and it’s making Joplin unusable for me. Here is the error log that is generated every time I try to sync from this new phone:
Yes, both devices are running Joplin 12.12.3.
The old iPhone does not use encryption. No client for this account has E2EE activated.
I have tried removing and reinstalling Joplin from the new phone, more than once and with a delay of several days + power cycling to clear any spurious cached data. The problem persists.
It seems like the same thing that happened to this person may have happened to me. But they were using Dropbox for sync, and were able to edit a json file to remove the spurious master key. I have no idea where this file would be found when syncing through a Joplin Sync server.