Preview is Tinted Green

Mostly it look like a GPU glitch, did you use any mp4 video file in your placeholder?

Pink or green previews are a relatively common issue when there is an issue with the drivers for your GPU/display card.  Here's one of many threads where it has been discussed in the past:

https://community.adobe.com/t5/Premiere-Pro/Preview-video-is-pink-green/td-p/9738703

When posting, especially with issues that may be hardware related, it's important to give details of your hardware, including:

• Operating System

• CPU

• GPU/Display card

• RAM

• Hard drive type(s) and capacity

• After Effects version used

Is this a template you purchased or downloaded? Your screenshot shows a bunch of nested comps and a very long comp. Most of my comps are one shot and under seven seconds. AE is not an editing app.

We have no idea what is going on in the comp or the nested comps, no system info, and no workflow details so your green preview could be poorly compressed footage, variable frame rate footage, GPU drivers, of a hand full of other problems. Without details and system info that's the best anyone can do to help you with your problem.