Email Error: SMTP Error: The following recipients failed

I have the same e-mail problem: Message I get is:Email Error: SMTP Error: The following recipients failed:
Then I phoned with my host: host gator and they told me everything seems to be set up right, but there might be a problem in the php script or the backend.
When searching for the SMTP error, I got the following:
/home/herb11/public_html/includes/classes/support/phpmailer.lang-en.php

Line #13 : $PHPMAILER_LANG["authenticate"] = 'SMTP Error: Could not authenticate.';

Line #15 : $PHPMAILER_LANG["recipients_failed"] = 'SMTP Error: The following recipients failed: ';

Line #16 : $PHPMAILER_LANG["data_not_accepted"] = 'SMTP Error: Data not accepted.';

Line #17 : $PHPMAILER_LANG["connect_host"] = 'SMTP Error: Could not connect to SMTP host.';

I am sorry, if the same questions where asked before, but I tried to find an answer and couldn't. I am also very new on this. Here is the website address: http://www.allnaturalherbaltherapy.com

Hope someone is able to help me :no:

"When" do you get that message?
There are about 30 different emails that Zen Cart sends. Which ones are failing for you? Which ones are working for you?

Also, when you click the "Reply" button below, there are several questions listed in the "Posting Tips" section of the screen ... please answer those as part of your reply.

Thanks for your reply.
I am using version 1.3.8
It's a new site, never upgraded it, only changed from Classic to Apple Zen.
No addons installed yet.
Only customization up to know was setting up categories, products, shipping, etc. The basic setup, try to learn as I go.
Not sure when the problem started.
I just run a test product. E-mail worked perfect. Only e-mail where the problem is, is the one on the Contact us page.

busiherb:

Only e-mail where the problem is, is the one on the Contact us page.
Aha -- now that is the important piece of information.

Chances are you've got an invalid email address specified in Admin->Configuration->Email Options in either of:

• Email Address (sent FROM)
• Email Address (Displayed to Contact you)
• Set "Contact Us" Email Dropdown List

Pay careful attention to the correct formatting of email addresses in those fields. The first 2 mentioned are just the email address, plain text. The dropdown entry requires a specific format.

Thank you so much. You were exactly right. That was so easy to fix and I read through the posts and tried everything, only not the basics.
I am feeling pretty stupid now, but without your advice I would have had a hard time. Once again, thank you, I really appreciate it.