Hi Chrisy,
Adding screenshots is a bit of issue at the moment....but try this:
Open a user account in "Active Directory Users and Computers" that isn't working.
Select the Account Tab.
You'll find that the "User logon name" is different to user id used to login to Office365 for that user.
These need to be the same for Lansweeper to link the AD account to and Office 365 account.
In my case, I was able to change the "User logon name" in AD to match the account used for Office365.
Hope this helps.
Regards,
Mark F