Service Desk not generating issues via email

Summary

The email address provided by the Service Desk feature appears to no longer automatically create issues in the Service Desk issue tracker when an email is sent to it.

Steps to reproduce

  1. Create a project on GitLab.com under a namespace that is at least assigned a Silver subscription.
  2. Navigate to the Issues > Service Desk section of that project.
  3. Make note of the incoming email address that users can use to generate issues via email.
  4. Send an email to that address.
  5. Observe that no issue is created in the Service Desk issue tracker.

Example Project

Reproduced in gitlab-silver/service-desk-testing.

What is the current bug behavior?

When an email is sent to the Service Desk email address no issue is automatically created based on its contents.

What is the expected correct behavior?

When an email is sent to the Service Desk email address, an issue should be automatically created based on its contents.

Relevant logs and/or screenshots

Headers from an email sent to the address in the above example project 
MIME-Version: 1.0
Date: Wed, 24 Jul 2019 14:09:47 -0700
Message-ID: 
Subject: Issue via email
From: Tristan Williams 
To: incoming+gitlab-silver-service-desk-testing-13473542-issue-@incoming.gitlab.com
Content-Type: multipart/alternative; boundary="000000000000b56284058e73ba99"

--000000000000b56284058e73ba99
Content-Type: text/plain; charset="UTF-8"


This should generate an issue via email.


--
Tristan Williams
Support Agent, GitLab.com


--000000000000b56284058e73ba99
Content-Type: text/html; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable


This should generate an issue via email.
=



-- 

 
Tri=
stan Williams

 Support Agent, GitLab.com<=
/div>






--000000000000b56284058e73ba99--

Output of checks

This bug happens on GitLab.com: 12.1.0-pre 96114344d1f

ZD: https://gitlab.zendesk.com/agent/tickets/127429 (Internal)