By default, only the customer, CC'd participants, and team members can add
comments to tickets via email. This setting allows any email address to create
comments.
When to enable
Enable this setting when:
Multiple people from the customer's side need to respond using different email addresses
Third-party vendors or consultants need to participate in ticket conversations
Use carefully as it may allow unwanted participants to add comments.
How to enable
Go to Admin Panel
Click on General
Click on Tickets
Toggle on Allow all emails to create ticket comments
Click Save changes