iCloud account showing twice in mail.
I recently logged out of iCloud on all my devices to try to solve an issue with Continuity camera.
After logging back in all my devices that issue was solved, but my iCloud account now shows up twice on Mail on the Mac.
I now get two of every email on the Mac, and cannot delete one of the mailboxes.
On Mail on my iPhone, only one account is showing, and there is only one copy of each email.
I've tried logging out of the iCloud account, and then back in, but I still have two identical iCloud mailboxes, each with all the same emails.
The 'All Inboxes' inbox shows two copies of every iCloud email.
Someone please help as this is very annoying!
Mac mini (M1, 2020)