I don't run Maddy, but I do run email for an organization of a few thousand people. It happens on occasion from various providers, The larger organizations(MS,Google,etc) will spam your logs SMTP errors with a URL. You visit the URL and do whatever actions they want that particular day and life goes on. It's not hard, but it is a bit annoying sometimes.
Generally if you have a static IP and you don't go being all stupid with spam, it's not THAT difficult, but you do have to jump a few hoops and then occasionally play wackamole with their spam prevention junk for the month.
It seems to come in waves, like email will be fine for a few months and then 1 provider after another will be all upset about gosh knows what that day and you have to visit URL's and push a few buttons.
I've been to lazy to track it, and the various reasons for that particular day, but this has been my experience. A few times a year you have to go babysit SMTP so email can be delivered again.
Not just MS, they pretty much all dump SMTP errors with URL's telling you about the SMTP error they gave you. Some are really awesome when you visit the URL, they say oh, do X and then you are good. Others say we just don't like you at the moment, with basically no detail... and then you get the full burden of figuring out why they didn't like you and trying again.
We host and manage the SMTP server(s) ourselves(We currently run Postfix). If you outsource your email to Google, etc, then they have to babysit the email logs for URL's, not you.
Generally if you have a static IP and you don't go being all stupid with spam, it's not THAT difficult, but you do have to jump a few hoops and then occasionally play wackamole with their spam prevention junk for the month.
It seems to come in waves, like email will be fine for a few months and then 1 provider after another will be all upset about gosh knows what that day and you have to visit URL's and push a few buttons.
I've been to lazy to track it, and the various reasons for that particular day, but this has been my experience. A few times a year you have to go babysit SMTP so email can be delivered again.