I suggest you update OneDrive for Mac to the latest version to have a check, for the old one you could drag it to trash.
(Please Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.)
After rebooting machine, please unlink your current account, add your another one, then selected the folders that you need to sync. And then added the previous account that you unlink.
Any issues you could post back.
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