cmayna,
Do you use TT on any other forum, or just SMF? If the former, have you experienced the same, or any other problems, on those forums?
The reason I bring this up is that TT had a system/software upgrade on 9/28/2017, about the same time that the migration to Xenforo commenced. The glitches brought about with TT's latest upgrade have created havoc for their users with login, and many other problems.
It may be a coincidence in timing with the problem being brought about by TT's upgrade or, as Al mentioned, Xenforo doesn't support TT. I do know that a good number of other forums owners and admins have expressed with TT, and are looking for an alternative mobile solution.