Blank page when logging to Clarity from VPN (from the office it works)

Products

• Clarity PPM On Premise

Issue/Introduction

Multiple users have an issue to connect to Clarity PPM via VPN, only 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 of the users: The issue started suddenly, it did not work for a while, then it worked for a week, then it doesn't work again.

Clearing the cache does not work. The VPN location does not matter, the issue is intermittent with all locations. We tried accessing another page with no luck. We tried adding KeepAliveTimeout and restarted Edge, no luck. The network admin reports that when it does not work it only issues 3 requests and when it does, it issues 5 requests.

Environment

Release : All Clarity releases

Component : CA PPM INTEGRATIONS & INSTALLATIONS

Resolution

When comparing the HAR traces, we found the request in working scenario has 2 extra headers - Sec-Fetch-Mode and Sec-Fetch-Site. These 2 headers are missing in the non-working request scenario. 

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

This issue is something related to LB configuration on customer side and related to these 2 headers. The customer should work with their IT support to resolve this issue with LB/Reverse proxy config