Sending of the message failed.
The message could not be sent because connecting to Outgoing server (SMTP) mail.ecloud.global failed. The server may be unavailable or is refusing SMTP connections. Please verify that your Outgoing server (SMTP) settings are correct and try again.
Do you still have this problem? I have just sent an email from my murena to my other private email account, and it worked. According to https://status.murena.io/, the email infrastructure is working, too.