Twitter returned the following error message:
The text of your tweet is too long.
And then it signs me out of twitlonger.. I've tried to clear the cookies, use a different browser, etc.. I think it's on your end.
This is most likely because you have links near the start of the post. Due to the new way Twitter automatically shortens URLs, it can sometimes end up with a longer URL than the one they're shortening, which can push the status that gets posted to Twitter over 140 characters.
I need to update to account for their new URL wrapping policy, but avoiding links in the first 100 characters should sort the problem in the meantime.