I just browsed the support forum and don't see that anyone else has had that issue.
Usernames on Tapatalk are required to be 3 characters, so I'm guessing that's the issue. I don't know why it took so long to catch up with that except that maybe because they have migrated boards from lots of platforms, which I think that they are just about done with, and are trying to make things uniform across the platform now.
Can you try changing it to something like ttt or *t*?
Did I accidentally change some setting or did Tapatalk change their board layout today? I am seeing a narrow list of threads and a statistics panel off to the side instead of at the bottom. I don't like it because I prefer the threads in full page and don't care about the statistics. So if it is something I did to change the layout, let me know!