Error Message Help

I just recently started requiring a paid membership to my site using s2Member Plugin. 2 of my 175 members have reported this Error --
503: Service Temporarily Unavailable
Too many IP addresses accessing one secure area!
Please contact Support if you need assistance.
Any insights? I'm hoping to grow the site to 1000 members
503: Service Temporarily Unavailable
Too many IP addresses accessing one secure area!
Please contact Support if you need assistance.
Any insights? I'm hoping to grow the site to 1000 members