Outgoing Mail Problems on 1.5.x

I am using opencart script until 1.4.9 released.

I have a few website using 1.4.9 and by this year 2012 i have started to use 1.5.x version for my new sites.

But in my 3 new opencart 1.5.x opencart websites, the outgoing mails is not working for notification invoices, newsletters and account creations.

When a new account created, notification mail comes to admin but not to goes to customer. Orders and newsletters didn't work ever.

I have use both PHP Mail settings and SMTP Mail settings which i got informations from my host company, but it doesn't work ever again. (The 2 website of them have different host companies and they have the same problem also)

I have never set these settings before on 1.4.x versions and all above problems has NOT occured ever and works perfect.

Can anyone explain is that a permanent problem for 1.5.x version? Or is it only for me?

And is there anyone can help me to solve this problems?

Thanks for all answers from now on.

I've not had any problems whatsoever with 1.5.x and mail, and don't know any clients that have either

if you search on forums you will see there is a general mail problem on 1.5.x version but not on 1.4.x versions.

I have a problem and trying to solve it, not to argue it.

thanks...

i think i have solve the problem

the problem causes from our server ip. my 2 different hotmail accounts couldn't get mails but gmail and yahoo get all mails without any problem

hotmail has been banned my hosting ip address

now i have post this subject to my hosting company and waiting for an solution or i will change my host...

in other words, you need to set up the SPF for your hosting, assuming you're not on a shared host. If you're on shared hosting, then this is quite common, as spammers generally use shared hosting, and as a result the IP address will get blacklisted

Yep. i got the same outbound email problem on 1.5.x. no solution yet...