Here is a similar thread about the same situation from 2020 and some things to check. At the time, it was an issue with Google Drive. Your picture doesn't indicate what assignment was being loaded -- is there a chance it was involving Google Docs? That error message could come from any site trying to load a document, so knowing what type of assignment it was could help.
Ultimately, though, the directions are in the message: Please try again later. The big players all monitor their systems to catch problems, so they're likely to resolve it without users saying anything. But if you can identify which server is having the issues, then you can check their status page.
