Cannot Add the HPE Content Manager To Outlook

We have discovered an issue in one users Outlook where the HPE Content Manager Add-In could not be enabled. We checked that the add-ins were enabled (In Content Manager 9) and initially on ticking to activate the add-in in Outlook nothing happens - the add-in just doesn't appear. But when we try and activate it again, the message below appears in the box and the load fails: 

'Not loaded. The Managed Add-In Loader failed to initialize.'

Anyone know how we would go about fixing this issue? For the record the Content Manager Version is 9.2, and the Outlook is 32 bit (CM is the same). Outlook is Microsoft 365. Any help would be super appreciated. Thanks in advance.