连接到 IMAP 时 SSL 协商失败（Debian Bullseye）

Question

All of a sudden my script can't connect to the IMAP server. It started failing during the night, so I guess something has been updated on the mail server?

I can connect via my email client Thunderbird though, but not via PHP IMAP

Could not connect to {mail.xxx.com:143/imap/tls/novalidate-cert/user=catch-all@xxx.com}
TLS/SSL failure for mail.xxx.com: SSL negotiation failed

code

public function connect(string $folder=''){
        $this->mailbox  = '{'.$this->host.$this->flags.'/user='.$this->user.'}';
        $mailbox        = $folder ?: $this->mailbox;
        
        if($this->stream){
            if(!@imap_reopen($this->stream, $mailbox, 0, self::CONNECT_RETRIES)){
                throw new Error($this, "Could not connect to $mailbox");
            }
        }
        else{
            if(!$this->stream = @imap_open($mailbox, $this->user, $this->pass, 0, self::CONNECT_RETRIES)){
                throw new Error($this, "Could not connect to $mailbox");
            }
        }
        
        ...
        
        return $this->stream;
    }

update

The IMAP server has been updated to Debian Bullseye which only accepts TLS1.2 or newer

The PHP version currently installed on the client is PHP 8.1.4 and also running Debian Bullseye . It should be compatible and up-to-date

Have found this "bug" https://bugs.php.net/bug.php?id=76928

Answer 1

Found a solution myself. If you just change /tls to /ssl with port 993 it works

The "bug" https://bugs.php.net/bug.php?id=76928

{mail.xxx.com:993/imap/ssl/novalidate-cert/user=catch-all@xxx.com}

The solution https://bugs.php.net/bug.php?id=78156