I had same problem. I am using PrestaShop 1.7.6.9 (en/fr). My solution was: Go to CONFIGURE->ADVANCED PARAMETERS->E-MAIL and then set: Set my own SMTP parameters (for advanced users ONLY) and fill all smtp parameters. and dont forget Clear cache
- Mail domain name: yourdomain.com
- SMTP server: yourdomain.com
- SMTP username: write your username
- SMTP password: write your password
- Encryption:None
- Port:25
I was using: Use PHP's mail() function (recommended; works in most cases) but in my case Prestashop only was sending emails to admin not to customers.
Hope it is work!