How to resolve "Visualforce refused to connect" error in Salesforce Visualforce page

Summary

When configuring Visualforce pages for the Connector for Salesforce and Jira, a "<Salesforce-URL>.jcfs.visualforce.com refused to connect" error is displayed.

Environment

• Jira

• Salesforce

Diagnostics Steps

Not applicable.

Cause

• Clickjack Protection setting being enabled in Salesforce.

• Visualforce Cross-Origin Security Headers setting being enabled in Salesforce.

Workaround

Not applicable.

Resolution

1. In Salesforce, go to Setup > Security Controls > Session Settings.
   

2. Scroll to Clickjack Protection > Uncheck the Enable Clickjack protection for customer Visualforce pages with headers disabled checkbox.
   
   
   

3. Scroll to Visualforce Cross-Origin Security Headers > Uncheck the Cross-Origin Embedder Policy (COEP) checkbox and then click Save at the bottom of the page.