This doesn't happen all of the time. I am not sure why it occurs especially with Esri's map services. When it does happen I either have to wait awhile and try again or open a firefox brower and the data comes in just fine. After that I can open an IE browser and it is working again. Does anyone have any ideas what may be causing this? It is driving me nuts.
All the responses from arcgisonline should come back as http/1.1. I would try to figure out why some are coming back (or seem to be coming back) as http/1.0. It doesn't sound like a browser cache issue (which is other times a usual culprit). The firewall could indeed be playing a role.
Thanks Bjorn. I will log it in, and once the problem is resolved (hopefully it can be resolved) I will post it on the forum. We have had a variety of outside users test our website without any problems. So, this is definitely an internal issue. -Alison
I would make sure the crossdomain.xml file is configured correctly. I had these same errors (but not using a Proxy) until i downloaded httpfox to troubleshoot where the trouble was. I basically copied Adobes crossdomain file pasted below just to get it to work and then tweaked it to make it more restrictive:
