My whatsapp is saying I can't make a call when I am already on the phone. I am not on the phone.

I have a BB classic and this was happening a few months ago and then all of the sudden it worked (I didn't do anything). I had been in Japan until a few days ago and it was working perfectly from there. I reloaded the app a few days ago because it expired. I talked to my friend in India 2 x and this morning I tried to call her and I am getting that message that I can't make a call because I am on the phone. When she calls me she gets the same message. Is there a fix?