Everytime I update hangouts I get this message whenever I open the app: "unkown issue with google play services". What is the cause of this problem? And how to solve it?
This problem can be caused by a old version of play services.
To update the version manually open this link on your android device and click update if there is an update.
Hope this solves your problem
Hope this way works for you. Keep in mind that setting names can be different from brand to brand.
Go to Setting > Security > Device Administrators
Un-check Android Device Manager
appsand uninstall updates to Google Play Services
Go to Hangouts, it should show a message saying that you need to 'update Google Play Services'. Click update.
After updating, Hangouts should not show the error message
Go back to Settings > Administrators and check Android Device Manager