Umbraco Workflow : Emails Sending Intermittently on Azure

Questions
1

Using Umbraco Workflow for content publishers in my client’s company. Notification emails send fine locally, they send fine on our test IIS server, but when we are on Azure they seem to happen sometimes not all the time.

On Friday we released a change to our site, entirely unrelated to Umbraco Workflow. But since then Workflow has refused to send out emails and we don’t have any errors in any logs.

We use MailJet on Port 587 (and we have tried 465) but nothing works.

Is there something in Azure we need to set/delete/update when we do releases?
Is the email queue code in Workflow in memory thus causing issues when we use Slots on Azure to swap staging to production?

Any help would be great as we are stuck with a very grumpy client and lots of unhappy content editors spread around the country not being told what is going on.

2

Do the mails actually hit the mail server? And are you on the latest version of Umbraco and workflow?

3

Do the mails actually hit the mail server?
They don’t. And no errors in Umbraco Logs or umbracoLog table or anywhere.

And are you on the latest version of Umbraco and workflow?
When the problem started a couple of months back, we were. We aren’t now because of the releases from both Umbraco and Workflow. But they are minor updates so I can only assume won’t affect those issues. But, it is fair to ask to be on latest which I will be scheduling in as soon as I can.