Account modification aborted

Error : Account modification aborted, there was a problem changing the user name.
When you go to Account Functions >> Modify an Account and try to change the username of domain, sometimes you may get the following error.
 There is currently a configuration error in the Apache configuration file. User name change aborted. Account modification aborted, there was a problem changing the user name.
Solution
1) Login to WHM
2) Click on  Server Configuration >> Tweak Settings
3 ) Search “Max cPanel process memory”
4) choose “Unlimited”
5) Click on Save Button
6) Done
Now try to replace the username and I am sure that you can repalce or edit the username without any error.