Hi all,
Just to let you know that we are still chasing the Hotmail/Outlook/Live support desk about these random non-delivery issues to Hotmail addresses. So far their response has been “We were unable to identify anything on our side that would prevent your mail from reaching Outlook.com customers.”
We have reminded them of the IP addresses that are being rejected and that we need them to look into Hotmail delivery issues…
Will update with more info as received. Thanks for your patience.
M.
The typical “we don’t find any problem” answer.
Have you tried Smart Network Data Service (SNDS) from Microsoft? It has helped us A LOT when an IP has been blocked.
You can check the status of your IPs there (first you gotta register the IPs of course). You don’t actually need to ask someone if an IP is blocked or not.
Once you detect that an IP is listed in blacklist, then you can request the removal from blacklist through this form.
It is worthy to check also here if your IPs are listed, since Microsoft uses Symantec Brightmail as you already know.
This are the ways we get our IPs removed from their blacklist. Usually it works within 48 hours. 
Hi
Yes, we are monitoring both SNDS & JMRP and are in constant discussion with Hotmail Sender Support. We are not on any blacklists (except for some guy in Chile) as you can see from MultiRBL.valli.org - Results of the query 178.33.199.69 (change the IP address as required)
M.
Update 2015-05-13.
Still no forward movement from Hotmail Sender Support even though they have all the information required.
Will update again later today.
Really sorry for this guys and gals, we are doing everything we can.
M.
Update 2015-05-14…
We have been delisted !!!
Now I am going to go and have all my teeth pulled without using anesthetic as that will surely be less painful than dealing with Hotmail support.
M.
ROFL (:LGH)