two sites can't see each other

[rondulus1]

Site A = x.y.40.110/255.255.254.0

Site B = x.y.41.70/255.255.254.0

Site C = x.y.41.124/255.255.254.0

All sites are from the same ISP and have the same gateway address.

I host a web site at A in the DMZ of a Pix 515E a customer at B can not get to. We have a backup site at C that can get to site A and ping both A and B. Both the A and B can ping C but not each other. B can get to other sites, and the remainder of our customers can get to my site.

I have no specific references to A in my config.

Any idea where to start?

Thanks

[shijasm]

Could you please more specific pls.

post your sample network diagram aswell.

[rondulus]

Disregard

Problem is with ISPs network