it could be that you problem is related to DMARC.
big changes are coming, big email providers like gmail,yahoo and I guess
also hotmail are implemeting DMARC. Use of Strict DMARC Policies will
make this big providers reject emails.
On 21/01/16 10:46, Per Jessen wrote:
I have a couple of customers complaining they are unable to send emails
to hotmail - typically they see rejects such as this:
550 SC-001 (BAY004-MC5F11) Unfortunately,
messages from 18.104.22.168
weren't sent. Please contact your Internet service provider since part
of their network is on our block list.
It doesn't affect all customers and checking our logs, it appears to
have started 18/1. Prior to that we had no problems delivering
outbound mails to hotmail, since then I see 149 bounces with the
The customers are on dynamic ranges from Swisscom, UPC and e.g. Virgin
(in the UK). Has anyone seen something similar?
Saverio Proto, Peta Solutions
Werdstrasse 2, P.O. Box, 8021 Zurich, Switzerland
phone +41 44 268 15 15, direct +41 44 268 1573