I’ve had a few complaints recently that the registration and password reminder system is not working properly on the site. This includes creating a Siebel Store account, as well as registering for the Blog.
The problem seems to be related to Outlook.com / Hotmail.com email servers rejecting the “New User Registration” emails. I suspect this is because the WordPress site uses the host SMTP server, resulting in a mismatch of domains that causes suspicion with that provider (and probably others).
I’ve now resolved this by using the Google Mail API to send all site emails. The result is that recipient mail servers should be far less likely to reject / block the email that is send on registration or when you request a password reminder.
Apologies for any inconvenience caused.