Thank you very much for the review!
Regarding to the customer email you can post a support message in the support forum and we will be happy to assist:
https://www.ads-software.com/support/plugin/appointment-hour-booking/
Some tips about the emails: You can check the location of the email settings in the following image:
https://apphourbooking.dwbooster.com/customdownloads/email-settings.png
… and please check the “from” email address used in the settings. Note that if you use a “from” email from a public email service like “@hotmail.com”, “@aol.com”, “@outlook.com”, “@gmail.com”, … it will be filtered by most antispam systems since the email will be identified as “not originated at the expected server”.
Try using a “from” address that belongs to the website domain.
Thank you!