Activations made by a user that has not logged in with their Redgate ID (e.g. activated manually) or is using a very old tool version (prior to the launch of user account licensing) will be recorded as Not logged in in the customer portal.
This is also the case with server based tools. SQL Monitor and SQL Backup are licensed per server so it's not conducive to tie a server license to an individual user.
Owners and administrators of the license can remove these anonymous users to free up the activation for someone else. But we cannot tell you on what server the license was activated or by whom. See Deactivating A License (Removing A User).
If you see Not logged in followed by your server name, removing these entries will deactivate the tool currently installed on that named server.