Good afternoon Oskrrrrr ,
Welcome to the Apple Support Communities!
It sounds like you are having issues with video streaming on your iPhone. Are you trying to play the videos in Safari or using the Netflix and YouTube apps?
- Try quitting Safari, Netflix and YouTube on your iPhone. Update it to iOS 13.6 and turn the iPhone off.
- If you have a Mac update it to macOS 10.15.6 and update iTunes, then turn off the computer. If you have a PC, update iTunes and turn the computer off.
- Finally, recycle the power to your modem/router to refresh the connection to the internet. Wait to turn on the iPhone and computer until the network status lights are showing connected on the modem.
The resources below will help you address this issue:
How to force an app to close on your iPhone, iPad, or iPod touch
Update your iPhone, iPad, or iPod touch
Update to the latest version of iTunes
Take care.