What is green box and how can I correct it?

Here is the screenshot

It appears to be some unit models failing to load. I would suggest reinstalling the game.

Ah, the famed English green box. Used against the French in the Battle of Basic Shapes.

But now seriously, the boxes themselves are telling you what to do “missing ABP, for more info look into your log files”. So take a look at your AoE 4 log files.