Invalid Certificate Microsoft Outlook cannot sign or encrypt this message because you have no certificates which can be used to send from your e-mail address.

Hi,

I have a problem when trying to sign emails with an X.509 certificate in Outlook 2010. I constantly get the error message. The certificate is Verified for the email address I'm sending from.

"Invalid Certificate
Microsoft Outlook cannot sign or encrypt this message because you have no certificates which can be
used to send from your e-mail address."

I have no problem with signing documents in Word 2010 with the same certificate, only when trying to send email.

Every check I can perform confirms that there's nothing wrong with the certificate. Yet, Outlook still says it is invalid.

I have even tried installing a second X.509 for the same email address just to check. Outlook doesn't seem to like either certificate.

I know this has been posted before, but I'm completely stuck here.

Thanks,

~Dan

April 6th, 2015 9:02am

Hi,

You may have checked the option "Encrypt contents and attachments for outgoing messages" in Outlook, please uncheck this to test if the problem persists.

File -> Options -> Trust Center -> Trust Center Settings -> E-mail Security -> Clear the checkbox "Encrypt contents and attachments for outgoing messages" -> OK.

Regards,

Melon Chen
TechNet Community Su

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April 7th, 2015 1:58am

Dan,

1. the sender must be the same as the email address in the certificate and

2. secure email must be enabled on the cert enhanced key usage property.

---

Jan

April 7th, 2015 2:22am

Hi,

I have "Encrypt contents and attachments for outgoing messages" unchecked.

I understand this checkbox is a common cause of the problem, but I'm still getting the error messagewhen it's cleared. 

~Dan

Free Windows Admin Tool Kit Click here and download it now
April 10th, 2015 12:33am

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