We operate several reasonably sized websites with approx 1m users.

Following a server migration 11 days ago, we are now using a new IP. During the migration, we updated our SPF records which is stated as being sufficient for SenderID to pick up the change in IP. We're also subscribed to the JMRP and process NDRs to remove users and keep our lists clean.

However, from day one of using the new IP we received 421 "we have limits for how many messages can be sent per hour and per day" errors.

I have been in contact with Hotmail Sender Support by email (I have a ticket ref if required) who advise me to wait until our IP's reputation has improved enough (from neutral) and advise me to use SPF/SenderID and JMRP (which we already do). I was told they use SenderScore which shows our email traffic as consistent for several days.

They refuse to help any further than to advise us to wait an unspecified amount of time (could be days, weeks or months). In the meantime, our customers cannot receive emails they pay us to receive.

I feel this is most insulting considering we've done what they suggest and we're a paid Microsoft Partner.

Can anyone advise on how to have this issue resolved? I'm out of ideas other than placing a notice on our websites that Hotmail/Outlook.com are refusing to accept our emails and that we suggest they use another email provider - not something I'd like to do.

Thanks.