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Support Article

After redirect from revere proxy ,button event is not working.



A web mashup implementation is displaying an initial harness. The user wants to replace the current harness with a different harness. In the gadget user is setting attributes like "display" with their initial harness name "XYZ". When gateway URL is referring directly to the pega devotement box url then it works but when redirecting through reverse proxy variable, initial harness is loading but any action on button, from that launching another harness is not working.

Error Messages

There is no error message on the screen. However Browser debug mode (F12) there is an error 

HTTP Error 400. The request URL is invalid

Steps to Reproduce

  1. Configure a web mashup implementation.
  2. Display an initial harness and in that harness place a button and on click of that button write code to replace the current harness with a different harness.
  3. Access the Mashup through an top level application hosted on IIS.
  4. After request redirects and displays the initial harness click the button to display the second harness.
  5. The button event doesn't triggers.

Root Cause

A defect or configuration issue in the operating environment. The Browser debug mode confirmed that the IIS is treating the URL invoked on click of the button as invalid and throwing HTTP Error 400. Directly accessing the URL also gave the same error. Some URL size restriction was causing the issue.


In order to resolve this issue the administrator added the following registry key as a REG_DWORD: 


This value defaults to 260, but in the failing requests pega have segments (URL length) of well over that number of characters. user set this value to 2048 and then rebooted the web server for the setting to take effect. 

Published October 27, 2016 - Updated December 2, 2021

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