SMTP Error 550

I'm getting a really interesting SMTP error, that I've not seen before....

A message that you sent could not be delivered to one or more of its recipients. This is a permanent error. The following address(es) failed:

firstname.lastname@company.com
SMTP error from remote mailer after RCPT TO:<firstname.lastname@company.com>:
host mail.company.com [xxx.xxx.xxx.xxx]:
550-Delivery from 64.87.17.247 rejected. Check at
550-http://www.commtouch.com/Site/Resources/Check_IP_Reputation.asp. Reference
550 code: tid=0001.0A090302.52E034E4.0027

The rejected, ok, but taking me to a website in the 550 error? Any thoughts on this? Apparently this e-mail to our company contained a link to another website, which we need to see.

Thanks in advance!