The site on WP stopped receiving emails. What could be the reason?

Question

WordPress

Hello.
Just yesterday, the site stopped receiving emails with order notifications and contact forms.
Moreover, the order notification is displayed in the Woocommerce admin panel, but the notification does not come to the mail.
And emails are not sent from contact forms.
Until yesterday everything was working. No manipulations with the site were carried out.
What could be the reason ?

Answer 1

Set up sending mail via SMTP. For example, through the WP Mail SMTP by WPForms plugin