"Wanna" ransomware outbreak. Please see this Sophos article sophos.com/kb/126733 for advice on how to protect your organization. Immediate action recommended.
Users of Reflexion Encryption may be experiencing an issue where they receive an NDR message stating that an email was not sent due to a "zixmail decrypt failed:[ZIX_CRYPTO_KEYNOTFND_ERROR]. ". Our Engineers are aware of this issue, and are currently working to resolve it. If you receive this message, please try to send the email again at a later time.