Not sure if it is related but I have noticed wierd mail behaviour on my new Sienna website as well.
If you would for example use the passrecover to have your password sent to you I did recieve the first email within a few minutes (not instant)! The second mail send to you after you click the confirmation links and which contains the new password came only after like 2 or even more hours.
Maybe the same goes for this? You need to be more patient?
I also had the email verification on when I just installed the latest version of Sienna but when I too recieved no mail on different test users I created I quickly disabled that feature. As far as I recall I never actually recieved those mails (but not sure on this).
Mail works just fine on this server, I run multiple sites on my own there, some sites for others and a webshop and all mail works perfect.
[add on]
Oeps, missed this before posting:
#35393 Trustmaster:
Also make sure "Administrator's email" setting in Administration / Configuration / Main settings belongs to the same domain you're sending from. Some hosts require that to be a valid account for sending.
That in fact could be the issue I will test/check/change this and get back about it.
<img src="http://www.armaholic.com/datas/thumbs/green-sea-battalion-uniforms-version-03-preview_4.jpg" alt="green-sea-battalion-uniforms-version-03-" />
