If you're using a knock-off version of WhatsApp, your account might be temporarily banned from the platform.
In its FAQ, the Facebook-owned messaging app says that people using modified versions of the app like WhatsApp Plus and GB WhatsApp will receive an in-app notification that their account is temporarily banned.
"WhatsApp doesn't support these third-party apps because we can't validate their security practices," the company said.
It's unclear exactly when WhatsApp started banning people using modified apps, but people on Twitter and Reddit began warning each other last week. WhatsApp didn't immediately respond to a request for comment.
The accounts aren't permanently banned. You need only switch back over to the main WhatsApp app. Just make sure you back up your chats first if you want to keep them.