We just stood up a Webex Meeting Server onsite, and we've had a couple users that we have had a heck of a time with. Just users that had previously had the Webex Assistant homed to the "old" webex.com service. Switching it to the new site appears to work, then the user typically cannot login via the link provided in a meeting invite.
Going to the URL of our Meeting Server allows them in. Uninstalling/reinstalling the productivity tool software does not seem to help. There has to be some silver bullet we are missing?