WHMCS Domain Search Not Working

Hi, I just noticed that my whmcs program isn't searching for domains:

https://drummerboyhosting.com/clients-portal/?whmcsportal%5Bpage%5D=whmcss%3A%2F%2Fwww.drummerboyhosting.com%2Fclients%2Fwhmcs%2Fdomainchecker.php

I tried searching and I keep getting an error:

The characters you entered didn't match the image shown. Please try again.
Enter the domain and tld you wish to use in the boxes below and click Lookup to see whether the domain is available for purchase.

I don't know what's happening can you help me figure out why it's doing that? Thanks!