'Unable to display fields. It seems like you don't have permission to edit this issue' in Salesforce

Problem

When trying to edit and Issue from Salesforce the following message appears:

Cause

• The JIRA Integration user does not have 'Edit Issues' permission in the specific JIRA Project, or
• The JIRA Integration user has 'Edit Issues' permission in the specific Jira Project but the Salesforce users attempting the operation does not have this permission, if they have a Jira account.

Diagnosis

To confirm it is a Jira permission problem:

• Sign into Jira directly using Integration User account to confirm that Issues in this Project can be edited, or
• Sign into Jira directly using the Salesforce User's Jira account to confirm that Issues in this Project can be edited. 

Resolution

Grant 'Edit Issues' permission in the Jira Project to the Integration User or the specific JIRA User (depending on the diagnosis above).