Long delay (or timeout) after submitting account details on order form

Question:

Q: When users enter their account details on the order form and click the Next button, there is a long delay and/or the browser times out. Why is this, and how do I correct it?

Answer:

After the user enters a username on the order form, iPanel/iHost must contact your control panel (CPanel, Plesk, etc.) to make sure that selected username is not already in use. It's likely that you have a significant number of accounts on your server, and your control panel is taking a long time to respond. In extreme cases -- particularly with overloaded Plesk and CPanel servers -- it can take 15 minutes or more for the control panel just to return a username list.

iPanel/iHost cannot (by default) just refer to its internal account list to verify that the username is available, because it's possible that you've created other accounts on the server (either manually, or with other billing systems, etc.), and iPanel/iHost would have no way of knowing about those usernames, which would result in a username conflict when iPanel/iHost attempted to provision the account.

If you're not going to be creating accounts outside of iPanel/iHost, however, you can disable this check by editing conf/conf.inc.php and adding the following line:

define('CHECKEXISTS_DB_ONLY',true);

That will tell iPanel/iHost to refer only to its own database for the duplicate-username check, and should eliminate the delay (and timeout) on the order form.