Default [Q] Twitter: No Notifications

Hey there,

I have a major problem with the official Twitter App. I don't receive any notifications. When I go into settings, my username and then Notifications, all the different kind of notifications are "OFF". Then I activate them (mentions, retweets, favs etc.) and I get the following message:

"You can only connect 25 devices to your account"
(at least this should be the right translation into English)

What I've done so far: Logged out from the app, revoked the access for the Twitter App at twitter.com/settings/applications and re-logged in into the app. Same problem.
Revoked the access of all apps in my account, deinstalled the app, re-installed it, same problem.
Reflashed the ROM, same problem.

I really don't know what to do anymore. There are no search results with this problem either... Do you have an idea?

Thanks in advance!
Phone: Nexus 5
ROM: Stock 4.4.1
Kernel: Stock