I'm not sure this is necessarily an issue with the CMV as much as it is with how I may have the proxy configured. I'm not sure exactly what to ask so I'll start with describing the symptom. When I am zoomed to a full extent and have few features being rendered the print widget generates a pdf just fine. When I'm zoomed in and many features are rendered the print widget generates an error.

Is this a result of the url length and the proxy coming in to play?

The error is:

POST http://myurl/myfolder/proxy/proxy.ashx?http://myurl2/arcgis/rest/services/Utilities/PrintingTools/GPServer/Export%20Web%20Map%20Task/execute 500 (Internal Server Error)

When I copy and paste the url in my browser the export web map task opens fine, through the proxy.

I have <serverUrl url="http://myurl2" matchAll="false"/> in proxy.config. The error message in the stack says ""Error: Unable to load proxy/proxy.ashx?http://myurl2/arcgis/rest/services/Utilities/PrintingTools/GPServer/Export%20Web%20Map%20Task/execute status: 500." Should this show the full url to the proxy?

I have 2 operational layers, one of which has a minimum scale defined. I noticed that the print works fine until the the minimum scale is reached on that layer. Once the minimum scale is reached, the error above is thrown. If you zoom out beyond that scale, the error is thrown until you refresh the page. I replaced my operational layer that had the minimum scale with one that that didn't (the same feature class) and the print works fine. I'm curious if this is expected (can others duplicate this) and what I might do to resolve it?

2 Answers 2


It sounds like CMV and the proxy are working fine and that the 500 error is generated by your ArcGIS Server. I would focus your investigation on the layer itself. Perhaps delete and republish the Map Service containing the offending layer. That simple step has frequently corrected similar issues.

I don't expect it is a limit on the length of url itself since it is using a POST request but that is possible. Check the server configuration. As a security precaution, many (most?) web servers are configured to limit the size of a POST request. You are probably not hitting that limit and I think the error code would not be a 500.

It is possible you may be running into limits of what the PrintTask can handle (memory?).


After contemplating more, it seemed everything was a symptomatic or incidental to some other problem (as @tmcgee suggests). I got to thinking, my viewer was an aspx page. I added a maxRequestLength to the web.config and it began working as expected. It was occasionally throwing a timeout error after that, processing some aerial imagery, so I added an executionTimeout to the web.config. It's been running as expected since.

  • 1
    I have the same issue. Could you provide the code you added? That would be a lot of help. thank you! :)
    – Brittany
    Nov 1, 2016 at 16:37
  • @Brittany: I added this in <system.web>: <httpRuntime maxRequestLength="102400" executionTimeout="36000" /> Nov 10, 2016 at 16:57

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