Access to _vti_bin/ListData.svc - cannot display the webpage

Hi all,

I am trying to view the xml of the lists within my sharepoint subsite, it works for one subsite, but doesn't work on the other subsite, any ideas why?

For example:

https://portal1/sites/mainsite/subsite1/_vti_bin/ListData.svc - Works can view XML

https://portal1/sites/mainsite/subsite2/_vti_bin/ListData.svc - Doesn't work, can't view, Internet cannot display the webpage.

I have full control access to both sites, please help!

Alan