Whitelist our outgoing mail server
System One uses SendGrid to send mails, our own mails and also emails that are sent on behalf of our users.
Before you read any further, Are you sure your domain is authenticated? If not, read the support article on domain authentication.
Starting March 2022 we've seen deliverabilty issues with a few customers that run a dedicated email security solution like Barracuda.
This while the customers' domain has been successfully authenticated (with SendGrid), so their automated DKIM security should work.
In the described situation, users have issues with emails that are sent from within System One to colleagues in the same domain.
The security solution on their email server blocks these emails and they are added to our bounce-list in SendGrid.
The first thing that should be researched, why our emails are being blocked by your server. Are we on a blacklist? Is something misconfigured?
A brute-force solution would be to whitelist the IP address of our mailserver at SendGrid:
This IP address last changed in December 2018
Once you made this change, please contact System One support to clear the bouncelist.
This information is ment for technical staff that maintains bespoke email infrastructure.
Whitelisting our mail server should be considered a last resort, as the bouncing of our emails might be indicate another configuration issue.