In WHM (Web Host Manager), each cPanel account is assigned a specific disk space quota based on the hosting plan or package. If a cPanel account reaches its allocated disk limit, the website or email services associated with it may stop functioning properly.
By following this guide, you can increase the disk space for any cPanel account in WHM, ensuring the account has enough storage for files, databases, and emails.
Step 1: Log in to your WHM Panel. Enter your root username and password to log in.
Step 2: Go to the Account Functions >> Quota Modification.

Step 3: Select the cPanel account and click on the Modify button.

Step 4: Finally, change the disk quota as per your requirement and click on the SAVE button.

This is it. The cPanel disk quota is increased.