Not all tiles load

[AndrewWhite]

We're writing a WPF application to be used on laptops in the field that use aircards to connect via VPN to our network where the map connects to an ArcGIS server using Active Directory authentication.  Our application currently displays one tiled mapservice.  But when the application starts and the map initializes, only about a third of the tiles load.  The MapProgressBar shows 100%.  This behavior occurs at all zoomlevels.  Obviously this is not a workable solution.

Is this behavior expected under the circumstances?  Are there client or server settings that would improve performance and allow these tiles to display?  Is there any data that would help us figure out why this is occurring?

Thank you in advance for any help anyone can provide us.

[dotMorten_esri]

Could you try starting up Fiddler (www.fiddlertool.com), and then run the application? Look at all the image requests sent to the server and what comes back. This would probably give you a better idea what the problem might be.

[EricWood1]

Using fiddler the tiles that do not load are returning a 502 error.  This appears to be the same error that we receive if we just unplug the network cable from a computer that is browsing the map.

Our suspicion is that this is generated when some sort of timeout is reached.  The 3G wireless connection is a lot slower than when the client is connected directly to the network.  Once the tiles fail to load, the map does not appear to try and load them again if you pan around.  Are there any timeouts on the client or server side that can be adjusted?

[AndrewWhite]

Are there any timeouts on the client or server side that can be adjusted?

Can anyone answer this? 

As it stands, the map is unusable in the scenario described above.  Any help would be greatly appreciated.