I had exactly this problem too. I elaborated below.
If you keep an eye on your logs, when your emails are being blackholed (it accepts them but it does not deliver them!) it does provide a link in one of the 550 status messages, where you can get yourself unblocked. I've elaborated here: https://news.ycombinator.com/item?id=31185297
However this only works temporarily, after a month you're back in the doghouse. Only senders which send a large volume of legit traffic are allowed. It's ridiculous but sadly true.
Edit: I found the message in my old emails:
---
550 SC-001 (BAY004-MCxxx) Unfortunately, messages from
XXX.XXX.XXX.XXX weren't sent. Please contact your Internet service provider
since part of their network is on our block list. You can also refer your
provider to http://mail.live.com/mail/troubleshooting.aspx#errors.
---
In that link the "SC-001" code also refers to that reputation thing. This was the same at outlook.com / hotmail.com and live.com . It did not, however, affect corporate customers using Office 365 / Exchange 365. Only customers of MS' consumer offerings.
My "internet service provider" was a legit colocation service and nothing funny was going on in their network by the way. Microsoft was the only party that had issues with my server. All known blocklists had no issues with it. It was just MS being difficult and making up their own rules.
Anyway going to that link there is a form somewhere to temporarily unblock it. Give it a try.. Perhaps you can create an account at live.com yourself and send a daily test email or something... I thought of doing this but eventually I got so frustrated I gave up on it.
> Only senders which send a large volume of legit traffic are allowed. It's ridiculous but sadly true.
That’s the thing I’ll never understand: why would one have to spam email to be considered not spam?
I wonder at which point it is legitimate to go full conspiracy theory, and suspect they’re just trying to block the little players so they can keep their relative monopoly. Maybe they don’t do it on purpose, but the way their anti-spam measures make life real hard for the little ones sure looks convenient.
If you get a 550 then it did NOT accept the mail. What grandparent is talking about would be the server replying with 250 OK and then neither delivering the mail nor sending a delivery failure notification.
If you keep an eye on your logs, when your emails are being blackholed (it accepts them but it does not deliver them!) it does provide a link in one of the 550 status messages, where you can get yourself unblocked. I've elaborated here: https://news.ycombinator.com/item?id=31185297
However this only works temporarily, after a month you're back in the doghouse. Only senders which send a large volume of legit traffic are allowed. It's ridiculous but sadly true.
Edit: I found the message in my old emails:
---
550 SC-001 (BAY004-MCxxx) Unfortunately, messages from XXX.XXX.XXX.XXX weren't sent. Please contact your Internet service provider since part of their network is on our block list. You can also refer your provider to http://mail.live.com/mail/troubleshooting.aspx#errors.
---
In that link the "SC-001" code also refers to that reputation thing. This was the same at outlook.com / hotmail.com and live.com . It did not, however, affect corporate customers using Office 365 / Exchange 365. Only customers of MS' consumer offerings.
My "internet service provider" was a legit colocation service and nothing funny was going on in their network by the way. Microsoft was the only party that had issues with my server. All known blocklists had no issues with it. It was just MS being difficult and making up their own rules.
Anyway going to that link there is a form somewhere to temporarily unblock it. Give it a try.. Perhaps you can create an account at live.com yourself and send a daily test email or something... I thought of doing this but eventually I got so frustrated I gave up on it.