array_diff_key function has something to do with the language JSON file.
Make sure /storage/language/engilish.json file exists on your server and has read permission (0755)
I will not be able to help everyone with server issues. Every server is a bit different can act differently based on the configs. That's the reason services like Docker exist.
One more reason for anyone who cannot manage all the server things by themselves, consider moving to Cloud Foodomaa later.