emails are going fine from all mailboxes to one gentleman except from SMTP relay server.
This occurs from any machine (I’ve tested both from my Workstation in Woking, and from several machines in the 172.24.72.* IP range)
Remote host said: 550 5.7.1 Service unavailable; Client host [22.214.171.124] blocked using FBLW15; To request removal from this list please forward this message to firstname.lastname@example.org
Discussion between MS and someone with a similar issue can be found here: https://community.office365.com/en-us/f/156/t/289633
So we probably just need to email email@example.com
.com quoting the IP 126.96.36.199.
… but I don’t know what CC policies are on that / whether it’s appropriate for me to do; I would have through that would be the MDS action to resolve issues such as this one?
can you help find the cause