What box? Sounds like you have a generic Android box running Kodi. You would be better off in one of the Kodi subreddit. unless your device runs a true Android TV build you won't get much help here.

So you have a generic box with illegal streaming add-ons you're using to watch movies, the movies are streamed from sites that go down all the time. It's either that the internet connection in your house is flakey (as in you have poor wifi in your room) or the hosting site is not providing content anymore for that add-on.

If you can try and use an ethernet cable rather than wifi or try and move it closer to your wifi hub. If that doesn't work then the add-on is likely to be broken, make a post in /r/addons4kodi asking for help or read their wiki.

My advice to you is to provide some relevant info about your product. It's like calling up a mechanic and not telling him what car you drive. He's not going to be able to help you at all.