cPanel File Manager "An error occurred. Your account may be over its quota or you attempted to upload a folder." when using CloudFlare

Symptoms

When a domain is using CloudFlare DNS and a file is uploaded through the cPanel File Manager, you may encounter one of the following warnings:

An error occurred. Your account may be over its quota or you attempted to upload a folder.

The file size exceeds your account remaining disk usage quota. Because of this, you cannot upload this file. Delete some files, or contact your hosting provider to request an increase to your account's quota.

Description 

When CloudFlare is hosting the DNS for a domain, CloudFlare limits upload size (HTTP POST request size) per plan type. This can cause the issue where it appears there are quota issues preventing uploads from completing.

Workaround

You can use one of the following methods to prevent this error from occurring:

• Access the cPanel directly using the accounts's IP address and port 2083:
  Accessing Your cPanel Account
• Disable CloudFlare proxying for your domain and access it normally:
  How to disable the Cloudflare proxy for your domain
• Upgrade your account with CloudFlare. CloudFlare provides different upload limits depending on the level of your account, which you can review here:
  Customization options and limits