I noticed that on some J! 2.5.x systems, activating the Newsfeed brings you to the Update key page instead of displaying the last changes of JCE. In J!3.x.x enabling works flawless.
It seems that module parameters haven't been configured properly. Please make sure that you are using a valid twitter username, and
that you have inserted the correct keys. Detailed instructions are written in the module settings page.