Has anyone use the MX Toolbox site? http://www.mxtoolbox.com/
Is this a good tool to troubleshoot our email delivery issue?
The reason I'm asking is, we have a client (pgal.com) that we can't deliver our emails to. It basically times out. So I use this website to run SMTP test and two of their three servers come back with failed delivery.
What would cause those delivery failure?
I'm just not sure, because they're able to receive emails from others but not us.
We're only having similar issue with 3 other clients, out of hundreds of our clients.