By default, WordPress uses the PHP mail function to send emails generated by WordPress or any contact plugin you may use.
The most common reason for not getting emails is that your WordPress hosting server is not configured to use PHP mail() function, In addition to this, sometimes email providers will flag or block emails that arrive from a different domain than they claim. For example, if your From Email is @gmail.com, but your domain is www.example.com, this domain mismatch may cause an email provider to block the email.
To resolve email delivery issues, we recommend using SMTP to send emails in WordPress. Unlike the PHP mail function, SMTP increases email deliverability by using proper authentication.
SMTP option is the only mailer that doesn’t use any sort of API. Instead, it uses classic SMTP (Simple Mail Transfer Protocol). Since its setup process is less lengthy than other mailers, this can make things easier for you in the short term.
You need to install an SMTP plugin to make it work, there are many SMTP available.
If you need a SMTP account Utixo provides an high quality SMTP product on the shop.