I have a current problem for over a week now. I use Sony Experia SP running on android and cannot send viber messages to only one contact who has an iphone. All my other contacts work fine. This irregular one already refreshed the application, but nothing happens. I do no suppose that I was blocked. We used viber for even voice calls before and now no text msgs, no photos, nothing gets through from my side (tries sending for some time then goes red as unsent and resending does not go through again), but I get everything from her. I have no idea what is going on. Can anyone help with advice? Thanks.