Hello podfeet,

I have once met the similar condition,but mine is when I logging in digitalocean.I use managed domain email for my account,and I have a time that I cant receive their email anyway.Then I submitted a ticket,the engineer told me that if one email address refused to receive their email,which usually determine digitalocean’s email is dust mail,it will return the email and if this occurred much,they will take the whole domain into blacklist,and so users won’t receive mail from digitalocean anymore.

But I haven’t met what you described,I think your customers maybe use their own domain as their email.Contact them and try to take digitalocean into whitelist.Thats what I can do.If it doesn’t work,commit a work-ticket.

Have a nice day.

Shiroka

Many of the addresses in Digital Oceans IP range are blocked by a number of big email providers. Google is pretty good, others, like Spectrum, are not. I fought this battle for about 6 months with many calls and escalations to email providers try to get IP addresses unblocked. I finally gave up, but the history is still visible in a DigitalOcean question here. I you need email to get delivered, use a service like SparkPost, SendGrid or AWS Simple Email Service (SES).