1 year after the last post, I know, but my App has 3 years working fine an now I'm having the same issue. I'm looking for help.
I have regenerated the Twitter Key and secret but have no success. I have checked the Twitter server's time and it mach my server's time.
Some clients can login and some others don't. One client told me that he cleared his history and after that was able to login.
I can't ask every one to clear their cache. I'm using now a meta tag avoiding to cache my site, but this is going to slow down every one.
Any one has found a way to solve this?