Hotmail / Outlook is having issues with accepting the incoming email at the moment.
Problem started around 18.00 GMT+2 (12 May) .
Please dont be surprised if you see below error in your logs :
Error: “554 Transaction failed” while connected from
Only several of Outlook mail servers having this issue which means you can send to the next mx server.
Please contact me if you need help with massive email queue.
This kind of error is related to email attachment which is too large, you can avoid this error if you slow down the speed of sent & make the email attachment smaller a little bit,
If not you just need to stop the send and reload the pmta so it will start again.