It sounds like you're having an issue with your Apple TV. It's likely that the problem is not related to the internet, since you've indicated that restarting the device fixes the issue temporarily. There are a few possible causes for this problem, including a faulty connection or a software issue.
One possible solution is to try restarting your Apple TV and then trying to play a movie again. If the problem persists, you may want to try resetting your Apple TV to its factory settings. To do this, go to the "Settings" menu on your Apple TV, then select "General" and "Reset". Choose the option to "Reset all settings". This will restore your Apple TV to its default settings, which may fix the issue you're experiencing.
Another possible solution is to try updating your Apple TV to the latest version of the operating system. To do this, go to the "Settings" menu on your Apple TV, then select "System" and "Software Updates". If a new update is available, follow the on-screen instructions to download and install it. This may fix any software issues that are causing the problem with your Apple TV.
If none of these solutions work, it's possible that there is a hardware issue with your Apple TV. In this case, it may be necessary to contact Apple support for further assistance.