Post SMTP blacklisted link

The Send a Test Email is also handy as way of checking the “spammability” of our own Post SMTP servers. Unfortunately, popular online tests like this: https://www.mailgenius.com/ give a steep negative score because the Post SMTP link has been found into blacklists, probably from the bad reputation of some of the testers.

A quick-fix would be to strip that link altogether:

/plugins/post-smtp/Postman/Postman-Send-Test-Email/PostmanSendTestEmailController.php in line 342:

'<!--<br/><span style="font-size: 0.8em"><a style="color:#3f73b9" href="https://wordpress.org/plugins/post-smtp/">https://wordpress.org/plugins/post-smtp/</a></span>-->',

Long term, to keep from tainting the brand, perhaps using an image instead of a link, or making the reference local to the tester.