Messages from gmail users are not send

See below copied from WordPress Codex – https://codex.www.ads-software.com/FAQ_Troubleshooting#E-mailed_passwords_are_not_being_received

Ensure Proper Return Address is Used

By default, the WordPress mailer fills in the From: field with [email protected] and the From: name as WordPress. This is fine if this is a valid e-mail address.

For example, if your real e-mail is [email protected], your host should pass the email on for delivery. It will probably send your mail as long as yourdomain.com is setup to send and receive mail, even if wordpress is not a valid mail box.

But if you set you real email as the From: address and it’s something like [email protected], the mail may not send because gmail.com is not a domain handled by the mail server.