Domain checker of WHMCS is not working with WHMCS-Bridge

Hi,

I am new to whmcs-bridge plugin.

My whmcs domainchecker.php stopped giving results. It is showing blank page after submitting domain name and captcha from wordpress site.

The url for domain checker on my website is https://dnhgeeks.com/customers/?ccce=domainchecker

After submitting a domain name, it is giving this error

Notice: Undefined index: main in /home/[username]/public_html/wp-content/plugins/whmcs-bridge/bridge.init.php on line 561

I am unable to understand what is wrong with my whmcs bridge integration.

Thank You

https://www.ads-software.com/plugins/whmcs-bridge/