How our email delivery failure nightmare started
At Bootstrap Digital Group, we recently encountered an issue with our email system. The issue left us unable to send messages to our clients and partners. We soon discovered that our hosting service had banned us from sending email. On top of that, we noticed our admin email account had an astonishing 120,000+ emails with the subject line, “Mail delivery failed: returning message to sender.”
Where we started: Hosting support
Initially, we reached out to our hosting provider for help, but they were unable to offer much assistance. Change your passwords, update your libraries, the standard boilerplate suggestions.
We were on our own to figure this one out. Furthermore, we learned that we could not send email from our domain until we cleaned up the mess the malware made and had the hosting legal team approve our request for reinstatement.
What was the issue causing domain wide SMTP error 550?
It turns out the issue wasn’t related to the mail system, mail was just a symptom of the issue. Rather, we discovered that some of our website files, including customer sites and older sites, had been infected with malware. What was also surprising was we had recently done security reviews and were confident we could prevent issues like this for us and for our customers who trust us to protect them.
How did we resolve the SMTP 550 error?
To resolve the issue, we had to scan all files using a new app under cPanel. From there we had to upgrade older sites to a new version, identify the infected files, repair them, and re-upload them as needed.
While we were working, sending email was down, as the legal team considered our reinstatement request. We learned, it would take longer than expected to resolve the issue. We had to overcome this challenge, and we ultimately succeeded on our second attempt.
Closing thoughts and learnings
This experience was a new one for us, and it taught us the importance of regularly scanning our website files. Also the importance of taking measures to protect against malware. We also learned that it’s important to have a backup plan in place for communication with clients and partners in case of an email system failure. We hope that by sharing our story, others can learn from our experience. Make sure to take steps to protect your own digital assets. Contact us for your own security assessment review with Bootstrap Digital Group.