Hi,

I am seeing an issue where Yahoo! returns an HTTP 504 error when the openid.return_to and openid.realm parameters are set to specific value (example:namespace.accesscontrol.windows.net), but not when they are set to a different value (example: namespace2.accesscontrol.windows.net).
If the user is not already logged into Yahoo!, the 504 error gets returned immeditately, and it happens intermittently (over 90% of the time).

Can someone advise on why this occurs? It appears that Yahoo! may be throttling the response to the URL with the specific realm/return value .

Example URL below:

https://open.login.yahooapis.com/openid/op/auth?openid.ns=http%3a%2f%2fspecs.openid.net%2fauth%2f2.0&openid.mode=checkid_setup&openid.claimed_id=http%3a%2f%2fspecs.openid.net%2fauth%2f2.0%2fidentifier_select&openid.identity=http%3a%2f%2fspecs.openid.net%2fauth%2f2.0%2fidentifier_select&openid.realm=https%3a%2f%2fnamespace.accesscontrol.windows.net%3a443%2fv2%2fopenid&openid.return_to=https%3a%2f%2fnamespace.accesscontrol.windows.net%3a443%2fv2%2fopenid%3fcontext%3dcHI9d3NmZWRlcmF0aW9uJnJtPWh0dHAlM2ElMmYlMmZ0YW5ndWl0byUyZmZhY3R1cmElMmYmY3g9JTJmJnByb3ZpZGVyPVlhaG9vIQ2&openid.ns.ax=http%3a%2f%2fopenid.net%2fsrv%2fax%2f1.0&openid.ax.mode=fetch_request&openid.ax.required=email%2cfullname%2cfirstname%2clastname&openid.ax.type.email=http%3a%2f%2faxschema.org%2fcontact%2femail&openid.ax.type.fullname=http%3a%2f%2faxschema.org%2fnamePerson&openid.ax.type.firstname=http%3a%2f%2faxschema.org%2fnamePerson%2ffirst&openid.ax.type.lastname=http%3a%2f%2faxschema.org%2fnamePerson%2flast