We first started getting bounce notifications around 7 hours ago, I'm surprised it took this long for Postmark to announce the service issue.

We're seeing responses like this in our logs:

smtp;550 5.7.1 Service unavailable, Client host [<ip>] blocked using Spamhaus. To request removal from this list see https://www.spamhaus.org/query/ip/<ip> (AS3130). [DM6NAM04FT060.eop-NAM04.prod.protection.outlook.com]

Historical "Time to Inbox" available further down on this page: https://status.postmarkapp.com/

Postmark was bought out in May. Just a coincidence, or possibly co-mingling IP addresses with the new overlords?

https://postmarkapp.com/updates/postmark-has-been-acquired-b...

I wish it would be permanent, all of these “marketing” and “advertising” companies just produce things that fill out inboxes with junk.

It's long been the case that esps emit the most junk, not marketing but actual spam: stolen credentials, many many vulnerabilities, trials etc

These days sendgrid is the highest followed by Google and mailgun, Microsoft used to be on top but they seem to have dealt with it a little (anecdotal logging for mail servers I manage)

Like most ESP postmark is used for transactional emails too (like password resets, confirmations e.t.c.).

In fact Postmark only supported transactional email (and had an approval process) in the past. It looks like they dropped that to pursue a larger market, with predictable consequences.

Good.