See how to respond to mail, or forward it to someone else.
If there are no mail types available for selection, this means the Project Admin has restricted the mail types used to send a response. Ask them to review mail rules and make sure the appropriate mail types are available for your organization.
If you receive an error 'Max Size of 4 MB exceeded', you'll need to remove any large images that have been embedded/pasted into the mail body. Large images can be attached to the mail instead. For any other errors, follow these troubleshooting steps.