Check to ensure that you aren't out of plan data.
You can try snoozing or turning of the Video Data Saver.
Do you know what kind of speed you're getting?
If device with which you're trying to watch videos is connected via WiFi, try a direct LAN connection, if you have the ability.
We're closing this thread since we never got a reply from you. If you still have concerns, please start a new thread and include a detailed explanation so we can more effectively help you.