Inability for Chrome to Edit MS Excel

Products

• CA Single Sign On Secure Proxy Server (SiteMinder)
• CA Single Sign On SOA Security Manager (SiteMinder)
• CA Single Sign-On

Issue/Introduction

Chrome browser users are unable to edit SharePoint documents in Excel.  The document opens, but when the user clicks the button to edit the document in Excel, the expected pop up never appears.  This is not affecting IE users, and is only affecting external users who go through an external reverse proxy.

Cause

The following header, set in the OWA SharePoint farm, was causing the problem:

Content-Security-Policy: default-src https: data: 'unsafe-inline' 'unsafe-eval' 

Environment

Release: MSPSSO99000-12.8-Single Sign-On-for Business Users-MSP
Component:

Resolution

Setting the value of this header to blank (no value) resolved the problem.