TL;DR: Emails containing a link to our company website are marked as Spam by different providers. How can I find the reason for this, and how can I stop it?
Several weeks ago, the company that wrote and maintaines our website did a PHP version update and made some changes to the code for this. We tested the website, everything seemed fine, but after the new version went productive, we could not sent mails outside. External partners could not answer us, even these mails were classified as spam (SMTP Message: '550-5.7.0 Message considered as spam or virus, rejected 550-5.7.0').
After some testing we found that every email containing the link to our company website was considered as spam - even an emtpy mail where I wrote www.company.com in it. And since the website link is added in the mail footer, we could not sent mails.
After we removed the link from the footer, we could send mails again - we had to tell external partners to remove the link from the previous messages, now they could mail us again too.
After a few weeks now we wanted to readd the link to the footer - and immediatly the spam classification restarted with multiple providers, so I disabled it again and no problem anymore.
I already checked our mailserver, our mail settings (mxtoolbox), our domain against different blacklists - nothing to report here.
My question:
- What could be the reason for our website beeing flagged as malicious?
- Is there a public black list where I can report this as false positive? Some kind of website reputation spam list? I only find black lists for SMTP servers or email domains (ours is not listed anywhere).
0 Answers