URL blocked by our ISA 2006 proxy server

We have URL data.import.io blocked by our ISA 2006 proxy server.

We receive two errors when logging in the Monitor section, however there is no rule or action definition of why blocked.

I have copied the errors below:

192.xxx.x.xxx 192.xxx.x.xxx     [proxy server]-  107.23.100.216 HTTP TCP - - -  Local Host External   Closed Connection    -    14/01/2013 11:57:48 14/01/2013 11:57:48 53951 80 0 11147 4870 0x80074e21 FWX_E_ABORTIVE_SHUTDOWN  0x0 0x0 Firewall -


192.xxx.x.xxx 192.xxx.x.xxx     [proxy server]-  107.23.100.216 HTTP TCP - - -  Local Host External   Initiated Connection    -    14/01/2013 11:57:48 14/01/2013 11:57:48 57423 80 0 0 0 0x0 ERROR_SUCCESS  0x0 0x0 Firewall -

At first we thought it was our Web filter, however we have disabled the web filter in our ISA Proxy & still get blocked !!

In I.E. 10 developer tools, on the Network tab - start capturing we get 404 result

Is it because of the ISA server cannot cope with .io domain, can anyone help ?