Mu4e suddenly stopped sending emails

[emails]

   Hi,

   I use mu4e on as my primary email client. last night, without changing
   anything on my system (that I know of), it stopped sending mail with
   the following in *messages*:

   [mu4e] Saved (8 lines)
   Sending...
   Sending via mail...
   open-gnutls-stream: make client process failed: Keine Route zum
   Zielrechner, :name, smtpmail, :buffer, *trace of SMTP session to
   [MY-SMTP]*, :host, [MY-SMTP], :service, 465, :nowait, nil,
   :tls-parameters, nil, :coding, nil
   Quit


   This is the relevant part of my config:

   (setq message-send-mail-function 'smtpmail-send-it)

   (setq mu4e-contexts
   (list
   ;; work account
   [My other account...]

   (make-mu4e-context
   :name "emails_jd"
   :match-func
   (lambda (msg)
   (when msg
   (string-prefix-p "/emails" (mu4e-message-field msg :maildir))))
   :vars '((user-mail-address . "emails@jonas-damm.de")
   (user-full-name . "Jonas Damm")
   (smtpmail-smtp-server . "[MY-SMTP]")
   (smtpmail-smtp-service . 465)
   (smtpmail-stream-type . ssl)
   (mu4e-sent-folder . "/emails/Gesendet")
   (mu4e-trash-folder . "/emails/Papierkorb")
   (mu4e-drafts-folder . "/emails/Entw&APw-rfe")
   (mu4e-spam-folder . "/emails/Spam")
   (mu4e-refile-folder . "/emails/Archiv")))))

   Thanks for any help!

   Jonas