Hello and thanks for reaching out to us! While I don't have any personal experience with Sucuri, there are certainly website protection tools out there that can mess with our crawl attempts. If you can send your campaign name and web address to help@moz.com, we'd love to take a look at that for you!
Wednesday Webinar Series
9/5/2012 The Help Team is proud to announce a new weekly webinar series just for our community members: Wednesday Webinars!