Okay, I will write a solution, who needs to solve this error now. This solution will only nessesary, if the connection uses SSL...
For POP3 connections:
Go to file /include/laminas-mail/src/Protocol/Pop3.php to Line 96 and replace
$this->socket = fsockopen($host, $port, $errno, $errstr, self::TIMEOUT_CONNECTION);
$context = stream_context_create([
'ssl' => [
'verify_peer' => false,
'verify_peer_name' => false
$this->socket = stream_socket_client($host.':'.$port, $errno, $errstr, self::TIMEOUT_CONNECTION, STREAM_CLIENT_CONNECT, $context);
For IMAP4 connections, you find the same code in:
/include/laminas-mail/src/Protocol/Imap.php in Line 91
There you find the same code to replace...
I hope this changes are useful for someone.
It's not an official solution, but it works.