Google Hangouts

Every since my IOS 8.4 update on my iPhone 5s my hangout application has stopped allowing me to video or voice call. I log in, verify my gmail account and try to video call and it gives error message "unknown account registration error". I have tried hard resetting my phone, deleting and re-adding application, and restoring my device from a back up. None of these options have worked. On my Samsung tablet hangout still works the same as it did before. Please help