This is an issue that the parent company of FlyerTalk, Internet Brands, is aware of but there is no fix for other than you requesting a change of your handle to one that doesn't include punctuation.
See this thread for a problem that is very similar to yours: https://www.flyertalk.com/forum/tech...s-profile.html Edit: Your question has now been moved into the thread that was linked, so there is no longer a need to click on the link.
That said, if you go through with the process of changing your handle for the above-stated reason, please take a look at this thread for guidance:
Change user name / username / handle: Can I? How?