Where did you see this message (salesforce, the support portal) ?
The support portal has been revamped, is redirected to a new site since 2 weeks.
Please check that you do not have a proxy/firewall that prevent you to be redirected.
Initial website :
http://splunk.com
* first redirection :
https://exsso.splunk.com/idp/startSSO.ping?PartnerSpId=https://PROD_SupportPortal_ExistingContact
* second redirection
https://splunk.my.salesforce.com/home/home.jsp
when i try to contact the support portal from splunk.com , it redirects to the sales force site and i receive that error. i tried several times. ive seen that error reported from many people when i searched for it in the web.