I am do not get emails about reservations. How to fix it ?

1) Firstly check SPAM / JUNK folder in your mail system.

2) Open Booking > Settings > Emails page and for each email template (switch tabs at toolbar) recheck that you have correct email addresses. Tip. Try to use insatead of complex email like this:
Booking System <info@your_server.com> just simple email like this info@your_server.com

3) Please be sure that you activated specific email templates for sending at Booking > Settings > Emails page.
Check-box status "Active" must be checked at each email template, that you want to use.

4) Check that your PHP mail function is working correctly. You can open your login page and try to retry the password, then check if you received email.

5) This is most common reason of not receiving emails !!!
If your emails aren't being received by Gmail, Hotmal, Yahoo Mail accounts, here's information that should help you understand why this is happening.

Issue description
Here is typical situation:
The admin email for your booking system is a “yahoo.com” account.
Customers were receiving emails, if they had a “isp.com” account but not a: gmail.com, hotmail.com, yahoo.com.au

Those emails were rejected by hotmail/yahoo/gmail servers due to their new email policy.
Error logs are showing to refer below links :

If your WordPress is sending emails from some custom email address (for example like this: ‘username@orion-dse.fastwebservers.com.au’), then you needed to enable SMTP authentication with WordPress site so the emails would send from your yahoo/gmail/hotmail email address instead of custom email ( username@orion-dse.fastwebservers.com.au - cPanel default username). This have to fix this issue.

You can fix this problem by installing the “Configure SMTP” WordPress plugin.
You can setup SMTP authentication through any WordPress smtp plugin.
Please refer https://www.youtube.com/watch?v=ZZPfkzEaJaQ

P.S. Thanks to dscottfl about this solution.

6) You can check the info about similar troubleshooting story here: https://wordpress.org/support/topic/e-mail-not-sending-3

7) If the issue still exist, please recheck ( with your hosting provider support ) email log file about the reason of not sending emails.

8) Finally if it's will not help try to change emails to wordpress@server.com , where server.com - your server. Here is more detail info about is issue.