Thanks Marg 7. beginning to look like it's a general problem with mail from Hotmail being rejected by Yahoo.co.uk. Does anyone know how to complain to Yahoo. The only link I can find is to report abuse.
Hotmail is increasingly unreliable. About 30 of us share one email address (on a private domain) for organising social events etc, and if I start a thread to the email using my webmail (also on a private domain), the hotmail.com users (but not the hotmail.co.uk users, oddly) never get that first email, it just vanishes in to the ether. We think it's something to do with Microsoft scoring stuff sent via webmail as high-risk spam *sigh* which wouldn't be a problem if the emails ended up in a spam folder, but they don't, they just vanish.
jolorna - thanks for the confirmation. It would still be interesting to have feedback from more users who have sent mails from Hotmail.com to yahoo.co.uk
I used to have a Tiscali e.mail address and some time back they had a problem where spammers were using Tiscali e.mail addresses (probably spoofed) to send mails. Many other ISPs then blacked Tiscali's mailservers affecting much genuine mail too. It took them quite a while to sort it out and I do have some sympathy for ISPs or webmail providers having to deal with this sort of activity. However they need to be totally upfront with users about what they are doing. If Yahoo.co.uk have declined to receive mail from Hotmail.com servers they should tell us.