On 10/11/2020 10:07 AM, Marc Roos wrote:
o16789123x54.outbound-mail.sendgrid.net.
The specific range of sendgrid looks like this[1]. So now you know they
use sendgrid and probably have access to a 'limited' dynamic ip range.
Now you can decide to reject email coming from (the whole of) sendgrid.
I am the one who is a client of sendgrid. Before subscribing to their
service (with low volume it is free) many of my messages were rejected.
They provide legitimacy. Highly recommended:
https://sendgrid.com/
Thanks!
-Ramon
