我不能让imap在本地主机上工作这是我正在尝试执行的代码：
<?php
/* connect to gmail */
$hostname = '{imap.gmail.com:993/imap/ssl}INBOX';
$username = '********@gmail.com';
$password = '****************';
/* try to connect */
$inbox = imap_open($hostname,$username,$password) or die('Cannot connect to Gmail: ' . imap_last_error());
这是我得到的错误
Warning: imap_open(): Couldn't open stream {imap.gmail.com:993/imap/ssl}INBOX in /opt/lampp/htdocs/test/index.php on line 7
Cannot connect to Gmail: Certificate failure for imap.gmail.com: unable to get local issuer certificate: /C=US/O=GeoTrust Inc./CN=GeoTrust Global CA
Notice: Unknown: Certificate failure for imap.gmail.com: unable to get local issuer certificate: /C=US/O=GeoTrust Inc./CN=GeoTrust Global CA (errflg=2) in Unknown on line 0