Not sure whether its a Snap issue or hotmail issue.
I am a Neighbourhood Watch co-ordinator and have an email group of 100+ residents that I send email to.
Over the last couple of weeks all of a sudden all the hotmail users emails are bouncing back with the message:
5.3.0 - Other mail system problem 550-'5.7.0 (BAY004-MC6F35) Message could not be delivered. Please ensure the message is RFC 5322 compliant.'
The addresses are hotmail.com, hotmail.co.uk, hotmail.co.nz, outlook.com, windowslive.com.
Ive done a bit of research and the only solution? I can find is to possibly add arrow brackets e.g <firstname.lastname@example.org> for all the email addresses that are bouncing back, which is needless to say a right PITA.