Have you tried deleting and reinstalling the app to check if that resolves the issue? For more help, visit the Hangouts Help Forum: https://goo.gl/KAuv1P . Hope this gets resolved!
Oops! Sorry about that. Please send a feedback report directly from YouTube with these steps: https://goo.gl/WdI0BK . While every individual report may not get a direct response, we do review everything and use the details to investigate and fix issues. Thanks.