User dont get email with key

I used the default php web api and setted up paypal.. Other thing except paypal i put false in payment settings.php but if my friend try to buy he wont get any email! Please help... My site http://skycitycz.ml/buy (im not from english speaking country and im begginer at web api so please help)

And how can i update turbo activate in my c# application?

You need to enable logging and see if PayPal is contacting the script. And you need to make sure emails can be successfully sent from your server (not as easy as it sounds).

If you want an easier method, just use FastSpring: https://wyday.com/limelm/help/automate-license-generation-with-fastspring/

How to enable logging and how to see if paypal contacting the script? As i said im new in these things and how to make email send from my server? Should i give it like my domain email account login somewhere?

It requires you set things up on your server. Plus it requires you setup a mail server such that customers will actually receive your emails (anti-spam systems are complex). This is a huge topic in itself.

If you're interested here are some topics to google to get you started:

1. DKIM2. SPF3. DMARC

It's a huge a complex topic. You'd be best off using a 3rd party email service (MailChimp, SendGrid, or one of the billion clones). Or just use something like FastSpring to handle the payments & emails end of things.