If encryption is enabled, Microsoft 365 secures the email using encryption keys.

Crossware Mail Signature cannot process encrypted emails as it does not have access to the encryption keys required by Microsoft for decryption.

Therefore the Crossware Mail Signature Service will not append a signature to the encrypted portion of the email, however a signature may be added to the plain text or html wrapper around the encrypted component.


Dynamic Signatures allows a Signature Configuration to be appended to a message, when the message is composed. As a result a message is sent with a signature, without the need to be processed by the Crossware Mail Signature Servers.

Related Products: CMS M365