Outlook/Hotmail soft bounce issue

[Lucas_Metherall]

Hi all, 

We have an engagement stream, PE 1, PE2, PE3, PE4. 

PE 1 was sent with a 99.7% delivery rate. The people are then funneled to PE 2, and it only had a 73% delivery rate. PE 3 then went back up to 99.6% delivery. I ran a smart list to see who had the soft bounces, and it is mostly Hotmail accounts, with one or two Outlook.com and live.com thrown in. 

Some sample logs:

554 5.4.7 [internal] (last transfail: 451 4.7.650 The mail server [185.28.196.157] has been temporarily rate limited due to IP reputation. For e-mail delivery information, see https://postmaster.live.com (S843) [BN7NAM10FT036.eop-nam10.prod.protection.outlook.com])

554 5.4.7 [internal] exceeded max time without delivery

Can anyone say why this might have happened? These people had emails delivered and opened before and after this occurrance. 

thanks!

[SanfordWhiteman]

Are you on a shared IP?

[Lucas_Metherall]

No, a dedicated. We use it for Aus/New Zealand, but it is separate from all other countries in the org. 

[SanfordWhiteman]

Do you know that these are the only emails sent to Outlook.com infrastructure in that time period?

[Lucas_Metherall]

To be clear of your question - you are asking if these bounces represent all email sends to outlook infrastructure, to identify if Outlook was accepting some emails but bouncing these ones? To query that I should ask MKTO for sent NOT bounced (OR dellivered) email (any) in [time period] address contains [Outlook/hotmail/msn/passport/live]?

[SanfordWhiteman]

Yes.

[Lucas_Metherall]

I had a look and yes, there were about 4,000 people with Outlook/Hotmail that receieved emails in the same time period, within a day of the email that generated the soft bounces.