Everything looks normal and working fine locally, but this is the error I get when it's uploaded to my server:

Warning: Invalid argument supplied for foreach() in /_app/core/api/file.php on line 537

This never happened previously, the only thing I've done is that I've moved my entire statamic site (files and folders) off my server, did some work on my server, and put them all back again.

What could be the issue and how do I fix it?

Answered by Aqeel Fikree! Go to answer.