Microsoft Outlook allows you to encrypt email messages easily. Encryption protects the data of the message until it reaches your recipients. Only the end-user will be able to view the contents of the encrypted messages. To encrypt an email message while composing, go to the File menu and select Properties. Click the Security Settings option and checkmark the Encrypt message contents and attachments option. You can now click Send. The message you have sent will be encrypted. But, some users are facing Outlook encryption problems. The error message shows that “Outlook had problems encrypting this message because the recipients have missing or invalid certificates.” The Encryption problems dialog box appears when Outlook is unable to encrypt emails. It may also occur due to conflicting or unsupported encryption capabilities.
If you are undergoing such issues, continue with the steps given below to fix the issue.