Hey MathewPotts,
It sounds like you're having some trouble with playing a movie on your MacBook Pro after purchasing the movie. I'll be happy to help out.
Take a look at these steps here to see if it helps out:
Restart your device, then try to stream or download your content again.
Learn how to restart your Apple TV, iOS device, or Mac.
If you're currently using a cellular connection, try to connect to Wi-Fi.
Make sure that your Wi-Fi router is 802.11a/g/n/ac compatible. Slower tiers of Wi-Fi connections might not be fast enough to stream the highest-quality video content (8 Mbit/s or faster for HD content).
If family members or friends are using the same Internet network, ask them to temporarily pause their Internet activities.
When multiple devices use the same Internet network for intensive activities such as gaming, video streaming, or backing up, it might slow down the speed of your local network.
See if you can stream your movie or TV show on another device using the same Wi-Fi or cellular connection. If you can't, the issue might be with your network and not your device.
Check to see if the iTunes Store has a service interruption, or check a third-party provider's website to see if they list any interruptions.
If there are service interruptions, try to stream or watch the video later.
If you're having trouble streaming your video content, you can also download the video1. Purchases from the iTunes Store and some third-party apps can be downloaded in the background instead and watched later. However, your ability to download the video depends on the file size and the amount of storage available on your device.
To download a purchased video, tap or click
. Downloading a video might take longer before you can start watching than if you stream it, but will allow you to watch the video all the way through without interruptions.
1 You can't download content to an Apple TV. You can only download HDR content on certain iOS devices, and you can't download 4K video content to any device.
If you can't stream or watch video content from the iTunes Store or third-party apps - Apple Support
Have a great day.