I have a php email script on a website that works when I send it to my yahoo account but won't work for different email addresses I have on a different server...
Could it be a problem with my server settings? dns settings? any ideas?

Thanks

What failure messages are you getting in /usr/local/psa/var/log/maillog when sending mail with the script?

Is it sending proper headers? Do you have Port 53 open in your filewall to allow DNS Zone transfers? I've seen some ISP's refuse mail if it's closed.

How do i check to see if it is sending proper headers and also how do I open Port 53 in my firewall?

and here is what I'm getting in my maillog

Sep 28 09:11:44 server1 qmail: 1127923904.019111 bounce msg 6586789 qp 13937
Sep 28 09:11:44 server1 qmail: 1127923904.019219 end msg 6586789
Sep 28 09:11:44 server1 qmail: 1127923904.022395 new msg 6586782
Sep 28 09:11:44 server1 qmail: 1127923904.022466 info msg 6586782: bytes 1867 from <#@[]> qp 13938 uid 2522
Sep 28 09:11:44 server1 qmail: 1127923904.026015 starting delivery 693: msg 6586782 to local postmaster@server1.pinnacleofwebhosting.com
Sep 28 09:11:44 server1 qmail: 1127923904.026045 status: local 1/10 remote 0/20
Sep 28 09:11:44 server1 qmail-queue: dwlib[13941]: mail: all addreses are uncheckable - need to skip scanning (by deny mode)
Sep 28 09:11:44 server1 qmail-queue: dwlib[13941]: scan: the message(drweb.tmp.wAhSGW) sent by #@[] to admin@alizeproductions.com should be passed without checks, because contains uncheckable addresses
Sep 28 09:11:44 server1 qmail: 1127923904.044547 new msg 6586789
Sep 28 09:11:44 server1 qmail: 1127923904.044589 info msg 6586789: bytes 1994 from <#@[]> qp 13942 uid 2021
Sep 28 09:11:44 server1 qmail: 1127923904.047951 starting delivery 694: msg 6586789 to remote admin@alizeproductions.com
Sep 28 09:11:44 server1 qmail: 1127923904.047983 status: local 1/10 remote 1/20
Sep 28 09:11:44 server1 qmail: 1127923904.048055 delivery 693: success: did_0+1+0/qp_13941/
Sep 28 09:11:44 server1 qmail: 1127923904.048167 status: local 0/10 remote 1/20
Sep 28 09:11:44 server1 qmail: 1127923904.048269 end msg 6586782
Sep 28 09:11:44 server1 qmail: 1127923904.207821 delivery 694: failure: Connected_to_67.15.2.29_but_sender_was_rejected./Remote_host_said:_501_<#@[]>:_domain_literals_not_allowed/

BTW: I haven't installed any firewalls on my server yet and I don't think plesk comes with it right?

Interesting error message. And points out that the other server you're trying to connect to (67.15.2.29) is misconfigured. Per RFC1123 (page 57 in case you want to look) mailservers MUST accept mail in domain literal format (eg user@[0.0.0.0]) for any of its IP addresses.

That said, your script really shouldn't be sending mail in this format normally. So I suspect that something isn't quite right in the mail headers From the above it looks like no From: address is being provided by the script, and it really should.

When you send one that gets refused you can get the message identifier number from the maillog. In the above, the number you're looking for would be 6586789. While you're SSH'd into the server do a locate 6586789 to find out where it's at.

That should give you three different locations. You'll want to view the one in the "mess" path. It'll look something like /var/qmail/queue/mess/X/6586789 where X is a number. Using Pico, Nano or Vi view the email and take a close look at the header information. Given your maillog entries I would pay close attention to the From field.

If you don't see anything that looks funny there, post the mail headers back here to the boards and someone will probably be able to spot it. My hunch is that no From: address is being sent by the script.

As to the Firewall... I seem to recall that Plesk now has a way to come with its own firewall. I don't use it myself so I'm not 100% sure on that. They never used to have a firewall installed. But if you don't have one, you get to get one installed ASAP! Without a firewall your machine is sitting out there just waiting for someone else to take it from you. There's a long thread around here somewhere that details all of the stuff a person really should do the moment they get a new server to make sure it's reasonably secure.

Adding just in case I misread something above...

If the 67.15 is your server or somebody you know you may want to run it through DNS Report, because there are a few additional issues.