如何使用php连接到Office 365共享邮箱文件夹

Question

I'm currently connecting our local website to our office 365 shared mailbox using PHP language.

I have tried accessing our personal office 365 email inbox and I have no problem accessing that. The problem comes when I try to access our shared mailbox connected to our personal emails. Below is the code that I have been using. Username and password Credentials are not actual for security purposes

$username = 'personal [e-mail]\sharedmailbox';
$password = 'password';
$mailserver = 'outlook.office365.com';
$port = '993';

$mailbox = imap_open( "{" . $mailserver .   ":" . $port . "/" . "imap" . "/" . "ssl" . "}INBOX",$username,$password);
$inbox = imap_search($mailbox, 'UNSEEN');
$nums=imap_num_msg($mailbox);


if($inbox){
        $ctr = 1;
    foreach($inbox as $i){
        echo $ctr.". ".$i."<br>";
        $overview=imap_fetch_overview($mailbox,$ctr,0);
        echo $overview[0]->subject. " " . $overview[0]->from . "<br>";
        $ctr++;

         }

}
else {
 echo "Failed to get Inbox";


}

imap_close($mailbox);

I expect it to show all the received email through the shared mailbox, however I encounter the issue below. Failed to get Inbox Notice: Unknown: IMAP protocol error: User is authenticated but not connected. (errflg=2) in Unknown on line 0

Notice: Unknown: User is authenticated but not connected. (errflg=2) in Unknown on line 0

Notice: Unknown: [CLOSED] IMAP connection broken (server response) (errflg=1) in Unknown on line 0

Am I doing something wrong? or is it not possible to connect through the shared mailbox.

Thank you in advance!