For Twitter social login, the callbackURL cannot contain any queries.
However, the URL provided by EasySocial contains a non-sef URL with a question mark, which cannot be used by Twitter.
I checked on the easysocial demo and it shows a SEF URL, but on my site I get a non-sef URL for Twitter:
Easysocial demo:
http://easysocial.stackideas.com/registration/oauthDialog/twitter
My Site:
https://www.mysite.com/index.php?option=com_easysocial&view=registration&layout=oauthDialog&client=twitter&Itemid=423