Getting around the "is a reserved username on this system" error when creating cPanel accounts.

Symptoms

Sometimes when creating a cPanel account, you will receive an error like the following.

Unable to create account. (XID vpycqw)test is a reserved username on this system. at /usr/local/cpanel/Whostmgr/Accounts/Create.pm line 623.

Description 

This occurs due to there being cPanel usernames that are reserved by cPanel for internal purposes.

Workaround

To get around this, you will simply need to change your cPanel username to one that is not reserved.  Please see the following documentation for more information, and for a list of reserved usernames for cPanel.

https://docs.cpanel.net/knowledge-base/accounts/reserved-invalid-and-misconfigured-username/

Please also note the following regarding the configuration of cPanel usernames as per the above documentation.

• Usernames may only use lower letters (a–z) and digits (0–9).Usernames cannot contain more than 16 characters.
• 
  Usernames cannot begin with a digit (0–9) or the string test.
• 
  Usernames cannot end with the string password.