If you are using Roundcube Webmail and notice that outgoing emails are not sending when BitNinja’s Web Application Firewall (WAF) modules are active, the issue is likely due to the WAF blocking certain requests.
You can quickly fix this by adding a custom domain pattern to the WAF module, where you disable our rule. This can be done at the Firewall -> Web Application Firewall tab.
Step-by-Step Solution

- Log in to your BitNinja Dashboard
Access your BitNinja control panel with your administrator credentials. - Navigate to the WAF Settings
Go to Firewall → WebApplicationFirewall tab. - Choose Where to Apply the Rule
You can add this rule on a single server or on a server group level, depending on whether the change should affect just one server or multiple servers - Create a Domain Pattern Rule
Add a new domain pattern: *roundcube*
This tells BitNinja to skip WAF checks for any URL containing “roundcube”. - Save Your Changes
Make sure to save the configuration so it takes effect immediately.