File and Folder Permissions

[Modrx]

I am getting the following errors when liking, commenting, or uploading images.

When liking:
500 Internal Server Error

When commenting:
Request failed with status code 500

Uploaded image:
Not showing due to file and folder permissions

If I set the permissions using the following commands, then the uploaded image shows but liking and commenting still doesn't work:
sudo find . -type d -exec chmod 755 {} ; # set all directories to rwx by user/group
sudo find . -type f -exec chmod 644 {} ; # set all files to rw by user/group