Blank page when logging to Clarity from VPN due to LB issue

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Article ID: 182912

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Updated On:

Products

Clarity PPM On Premise Clarity PPM SaaS

Issue/Introduction

Multiple users have an issue connecting to Clarity via VPN, only a blank screen is displayed. This is the case for all environments and all browsers. If the users go to the office, it works.

For some users, it works consistently, for some it doesn't work intermittently. According to one user: The issue started suddenly, it did not work for a while, then it worked for a week, then it doesn't work again.

Additional troubleshooting information:

  • Clearing the cache does not work.
  • The VPN location does not matter, the issue is intermittent with all locations.
  • You tried accessing another page.
  • You tried adding KeepAliveTimeout and restarting Chrome/Edge.
  • The network admin reports that when it does not work it only issues 3 requests and when it does work, it issues 5 requests.

Cause

If you compare the HAR traces, you find the request in the working scenario has 2 extra headers:

  • Sec-Fetch-Mode
  • Sec-Fetch-Site.

These 2 headers are missing in the non-working request scenario. 

While these headers are not used or expected by the Clarity server, according to https://www.w3.org/TR/fetch-metadata/#sec-fetch-mode-header these headers might be used by layers before applications like Load Balancer (LB), Reverse Proxy etc, to establish trust between client and server even before passing the request to actual application. 

Environment

Release : All Clarity releases

Component : CLARITY INTEGRATIONS & INSTALLATIONS

Resolution

Review the HAR traces to see if the above-mentioned cause is the reason for the issue. If so, this issue is something related to the Load balancer (LB) configuration on your side and related to these 2 headers, so you should work with your IT support to resolve this issue with LB/Reverse proxy config.