From Spry Wiki
A great site to check on issues with your mail server is mxtoolbox.com. You can supply your domain name and run a couple of different tests to check the status of your mailserver and to see if you are on any known Spam Blacklist.
- Navigate to http://www.mxtoolbox.com/ and enter your domain name in the MX Lookup field.
- MX Toolbox will then query your domain to find out the mailserver settings. Click Diagnostics to run a simple check on your mailserver health;
- The results should be similar to the ones below. You want to make sure your server responds is a decent amount of time and does not act as an open relay for spammers.
- Go back one page in your browser and select Blacklists to see if you have been blocked by any of the know blacklists.
- Now you will see the results as all of the known blacklists are queried.
- And of course we are not on any blacklists!