SUMMARYThis article describes how to customize the Challenge Response message and it's confirmation URLs in case of multidomain configuration.
WORKAROUND
Go to Anti-Spam -> Challenge Response tab. The Customization section is shown below.

The URL, in most cases, should be left as the default. It should only be changed if:
- You are running your Web/Control Service on a port other than 32000. Then change the port number accordingly.
- You are running a multidomain configuration with a virtual host for each domain. This is discussed at the end of this section.
The Challenge e-mail sender option sets the SMTP Sender address. Again it is recommended to leave it as default, blank. Use of this parameter can cause a loop between your servers whereby each server keeps auto-responding to the other.
To customize the message itself click the Message... button and the message template dialog is displayed:

Fill in the From and Subject fields as you would like recipients to see in their e-mail clients.
Edit the message body to meet your needs.
Variables can be used as shown above (enclosed in '%%') and the %s variable can, and should, be used to display the URL the recipient must visit. This is evaluated to the URL set in the customization dialog.
Multidomain configurations
If you host multiple domains you may want to customize the Challenge Response URL with the %%Recipient_Domain%% variable.
Let's assume you have two domains:
- domainA using host webmail.domainA.com
- domainB using host webmail.domainB.com
Enter http://webmail.%%Recipient_Domain%%/challenge/ as the URL and it will be changed to
- http://webmail.domainA.com/challenge/
or
- http://webmail.domainB.com/challenge/
accordingly.