If you like to watch on your Samsung Galaxy S5 via the app Youtube movies, then it can happen suddenly, that this does not work anymore and you receive an error message. If so, then you can use the app Youtube as follows again make it work:
1. The app Youtube on the Samsung Galaxy S5 reset. This goes as follows:
Open from the Home screen of your smartphone:
Menu -> Settings -> Application Manager -> Tab "All".
Search through the list for "Youtube". Tap the entry to to open the app info to it. Now select the buttons in the following order:
Force stop
Clear cache
Delete data
Uninstall updates
Launches the Samsung Galaxy S5 then reinstall to make the changes effective. Then the Youtube app should as usual play all videos. If not then use our second solution:
2. Wipe cache partition to perform (no data will be lost!)
The app Youtube on your Samsung Galaxy S5 should now work again as usual and play the videos.