(PHP 8 >= 8.2.1)
imap_is_open — Check if the IMAP stream is still valid
Exemplo #1 imap_is_open() example
<?php
$mbox = imap_open("{imap.example.org:143}INBOX", "username", "password") or die(implode(", ", imap_errors()));
imap_is_open($mbox);
// ...
?>