mail in php (no replies)

I'm trying to use mail in php to generate and send emails. I'm using settings as for Thunderbird (which sends emails OK) with code:

ini_set('SMTP','mail.overssl.net');
ini_set('smtp_port', '465');

ini_set('sendmail_from','rogerkeeling@f2s.com');

$ok=mail($emailTo,$emailSubject,$fullMessage);

but the mail() function just loops indefinitely.

I can run mail.overssl.net on a browser (Chrome) as webmail, but have to enter a password. I can see no way to enter a password in php.