Returning User Can't Connect to 3DX From CATIA

Hi all

We have a guy who used to work for the company a few years back, and has now returned. He's been given a new 3DX account. But, he has cleverly ticked the "remember me" box in the 3DX connector login pop-up in CATIA then entered his old credentials. Now when he tries to connect he gets this message:

His old inactive account is not visible in the members management dashboard, however, if I search the old collaboration & approvals environment for "person: his name" I see both accounts, one active and one inactive. But I don't seem to be able to delete his inactive account from here.

I also got our IT team to uninstall and then reinstall his connector (B425xcadconnector) in the hope that it would offer him a fresh login screen, but somehow it has still remembered he was trying to connect to the old account and displays the above message.

Any admins seen this before? How do I reset that login screen for him?