Suddenly No email on successful transaction

Nither the admin for customer is getting email's on a successful transaction

I have not changed anything on the server and my host is a friend of mine's company and he says they haveing touched the server in forever.

It literly just started happening.

Here's what i get.
Paypal order -> admin and customer get paypal email but no zencart email
check/money order -> both customer and admin get email but there both text. I know for sure that both the customer and the admin are set to html.

I've also went to ipncheck and ipn main handler and i'm getting no errors.

I've installed zen a hundred times and know a good bit but this is totaly baffleing.

Please only reply with valid solutions or sujestions.
Useing Zen 1.3.8a on DB 1.3.8a

Thanks
William

First, the "literally just started" situation is the first red flag. This almost always reflects something going wrong on the server.
Since you say your friend who runs the server claims to have changed, nothing, it could mean that any automatic server updates for spam rules might have triggered certain kinds of messages to go out differently than they did before, including stripping off portions of the email it doesn't like. Your hosting friend might not be aware of the changes, but he's the only one who can disable the auto-added rules, etc.
Another concept of "blacklisting" is a common cause of mail non-delivery; however, you're not saying emails aren't delivered. They're just not showing in HTML format. So, I rather doubt that blacklisting is your problem; however, it's worth checking whether your webserver is on any blacklists.

Next, if you claim you've not changed anything on the server, do a complete file-comparison between the server and your most recent "known to work properly" backup, looking for changes and additions and deletions of files and file-content.

Next, if you're convinced that the code on the server is identical to what it was when it was working properly, you can get yourself some proof that you're delivering HTML content to the mailserver (so your hosting friend will have to figure out why it's not delivering the HTML portion) by turning on email archiving. If you turn on email archiving, then all the content that was sent to the mailserver will be stored in the database, allowing you to see it in the format in which it was intended to be delivered. There's an email archive manager addon that lets you view the database content via your admin area too.
If you find the email archive records do have the HTML content archived, the problem is happening after the email leaves your server and gets onto the hosting company's mailserver.
If the email archive records do not contain HTML content, then somehow you've changed the email settings so that HTML content is no longer produced.

wlamoreaux:

Paypal order -> admin and customer get paypal email but no zencart email

I've also went to ipncheck and ipn main handler and i'm getting no errors.
What you describe suggests that either the PayPal server cannot talk to your server successfully, or your PayPal profile has IPN notifications disabled.
What's showing in the PayPal debug logs?
http://www.zen-cart.com/forum/showthread.php?t=61199
http://www.zen-cart.com/wiki/index.php/PayPal

on the same serer that has this zen installed there are about 30 other clients of mine that have the same exact zen with just about the same plug in's if not more.

There's is working fine.
so again.
verified with the email archive manager.

New cust sign up. (text only) both admin and client
New order (paypal) text only - client only. no admin email
new order (check money order) text only - both admin and client
news letter (text only) all clients. all 5000 of them and did a db query. 4786 are set to html
admin email via the admin panel.
only text no html

wlamoreaux:

on the same serer that has this zen installed there are about 30 other clients of mine that have the same exact zen with just about the same plug in's if not more.

There's is working fine.
so again.
verified with the email archive manager.

New cust sign up. (text only) both admin and client
New order (paypal) text only - client only. no admin email
new order (check money order) text only - both admin and client
news letter (text only) all clients. all 5000 of them and did a db query. 4786 are set to html
admin email via the admin panel.
only text no html

On the assumption that the email archive manager is what told you that those emails went as text-only (I'm slightly uncertain just because of your punctuation and spacing), then it appears that your Zen Cart files are what's causing the emails to be sent in text-only format.
If that's the case, and you have other Zen Cart sites on the same server which are sending emails in HTML format when the customer has selected HTML format, and you have the "Send emails as MIME/HTML" enabled, then the PHP files (and /email/*.html template files) in your "broken" site would have to be different than the files in one of your many "working" sites.
... in which case, I recommend a comparison ...
http://www.zen-cart.com/wiki/index.php/Troubleshoot_-_Diagnosing_Obscure_Issues

You might also try the PHP Debug Logging utility mentioned in (step 2a of) this FAQ, not so much for diagnosing blank screens but for trapping any PHP errors, such as silent failures when looking for email template files etc: https://www.zen-cart.com/tutorials/index.php?article=82

Side question: how many languages are active on your "broken" site?

Yes the archive manager is what is saying text vs. html.

but what's getting me is that it just started happening. nothing has been changed. our server does a backup every week of everything on the server and i've compared a known working set to the current set and nothing is different.

that's why i'm posting here. i'm at a complete loss as to why it's doing this now.