I'm using Ubuntu 14.04 and Firefox 45.2.0. Since the latest update for Firefox, I can't send any messages to recipients who have an account wit web.de. All other accounts are send like before. With web.de I get this error message: ----------------------- Reporting-MTA: dns;cpsmtpb-ews01.kpnxchange.com Received-From-MTA: dns;cpsps-ews12.kpnxchange.com Arrival-Date: Sun, 24 Jul 2016 10:22:47 +0200 Final-Recipient: rfc822;erwin.bausdorf@web.de Action: failed Status: 5.6.1 Diagnostic-Code: smtp;554 5.6.1 Body type not supported by Remote Host ---------------- Greetings Herman Willems