WordPress using a PHP mail function by default, when the hosting provider disabled PHP mail function on servers due to security reasons you need to use SMTP. The most popular WordPress plugin is WP Mail SMTP.
To use SMTP to sending mail from WordPress install this plugin. If you don’t know how, let me know in comment.
If you installed this plugin will show new element in menu Settings -> Email. Go there. You will see similar options available like in the picture below.
From Email – this is your email. Mails will be sent from this email
From Name – this is your name. Mails will be signed this name.
Mailer – method of sending mails. The best options when you installed this plugin because your form not working is first “Send all WordPress emails via SMTP.”
Return Path – check if you want to match the return path for your mails to the sending email.
Further settings apply SMTP options. You can get them from your email provider.
– you can SMTP host from your email provider
– you can SMTP port from your email provider
Encryption – use SSL encryption, it’s recommended option
Authentication – use SMTP auth, because most providers requires authentication
Username – login to your mail box
Password – password to your mail box
Below is a list of SMTP Host and Port of popular email provider:
Gmail SMTP Settings
– 465 for SSL, 587 for TLS
Yahoo SMTP Settings
– 465 or 587
Live, Hotmail or Outlook SMTP Settings
Mail.ru SMTP Settings
Yandex Mail SMTP Settings
Some of a providers requires your action when you connect to your mail box via SMTP. Just follow in the instructions in mail.