Background:

When installing specific plugins for Teams, ServiceNow creates HTTP response headers to address Cross-Origin Resource Sharing (CORS) between Microsoft and ServiceNow, however, these headers don't apply to all pages. As a result, some pages like a link to a KB article or an incident record will not be able to display within Teams. To address this, we'll create a new response header to give permission to teams.microsoft.com for all ServiceNow pages.

Known Issue:

Use a custom portal instead of Employee Center and/or installed "Conversational Integration with Microsoft Teams" v3.0.6

Note: To change Employee Center to a custom portal, change the value for sn_now_teams.portal.suffix in sys_properties.list.

Solution:

1. On your ServiceNow instance, elevate your admin role to "security_admin".
2. Make sure you are in Global scope.
3. Go to sys_response_header.list
4. Click on "New" button.
5. Fill out the following:
   Applies to: All Pages
   Name: Content-Security-Policy
   Value: frame-ancestors 'self' teams.microsoft.com *.teams.microsoft.com

After creating HTTP Response Header: