Dynamics GP Workflow intermittent emails failing

We have had an increase in cases with intermittent workflow emails failing.  Some of the Workflows have worked for years so we know the configuration is valid, but they are now becoming less reliable. 

The cause has to do with a change that has long been in the works.  After several announcements and delays the TLS changes have been updated on the SMTP endpoints on the Exchange team side.  Workflow uses SMTP as the transport for sending the emails.  The following blog explains what they have done

New opt-in endpoint available for SMTP AUTH clients still needing legacy TLS - Microsoft Tech Community

In that blog they provide a way for machines such as copiers to send emails using a legacy endpoint.  Software such as Dynamics GP can also use the smtp-legacy endpoint to continue to send SMTP emails.

The general configuration steps are covered in the following document

Opt in to the Exchange Online endpoint for legacy TLS clients using SMTP AUTH | Microsoft Docs

For Dynamics GP you will need to follow the steps to Opt in to the client legacy endpoint in your Office 365 tenant.  Connecting to your tenant using powershell is beyond the scope of this blog but once connected you would run the following powershell command

Set-TransportConfig -AllowLegacyTLSClients $true

And to view the status would be the following command

Get-TransportConfig | Format-List AllowLegacyTLSClients

Once the above Opt in has been set the only other part in GP that needs to be updated is the SMTP server in the Workflow setup window.  Microsoft Dynamics GP>> Tools>>Setup>>System >> Workflow Setup