Emails are not being sent to members

[Kalan]

I've done quite a few searches and am still coming up with a problem configuring my server and/or EQDKP-Plus software. I'd appreciate any help provided.
Member registration emails are not being sent from the server. I have tested this with 2 separate test accounts with different email addresses and outside help. The program in question is EQDKP-Plus with a php database installed. The port it is using is 80. I've opened a ticket, one of the support asked me to post here to get more exposure.

The settings inside the program are:

Sendmail - Mailer (I've also tried PHP-Mail-Function and SMTP-Server, none of these 3 settings seem to work)
admin@imperialrevenue.site.nfoservers.com - Mail from (address)
/usr/sbin/sendmail - Sendmail-Path
mail.nfoservers.com - SMTP-Host
admin@imperialrevenue.site.nfoservers.com - SMTP-User
********** - SMTP-Password

Thanks for your time and any help you can provide.

[Edge100x]

Is it posting an error message that we can analyze?

[Kalan]

I actually think this was caused by GMail acting up tonight. All the test emails were sent out but GMail just delivered them a few minutes ago. I retested and it delivered the email instantly. Thanks.

[Edge100x]

This also may have been a glitch on your webhosting machine, as I twiddled a firewall setting and restarted Postfix to be safe. In any case, I'm glad it's working for you now .

[Kalan]

Thank you for all the help.