Problem

Create issue post function is not working when issues are created through email, however it is working as intended when issue is created by logging into JIRA.

Diagnosis & Symptoms

• The post function comes from third party plugin
• The post function can be updating a custom field or something similar
• Further investigation shows that if the relevant permission are granted to Anyone, the post function can be executed successfully
• For example, if the post function is unable to update Epic Link, grant the Edit Issue and Link Issue permission 

Cause

It is possible that the post function is not executed with a valid user with the relevant permission when the issue is created through email.

Workaround

Consult the plugin vendor for more information.