Windows 7 Pro, Office 2010 Pro. I have three IMAP accounts on my laptop. I have three digital certificates from Comodo, one for each account. I have been using these certificates with these accounts since April, signing all messages and encrypting messages from one account. All three certificates are valid until 2020.
Two days ago I started getting an Invalid Certificate message (Microsoft Outlook cannot sign or encrypt this message because there are no certificates which can be used...) for every email I sent from each of the three accounts.
When I click on Change Security Settings button I see that Add digital signature is checked (as it should be). Security Settings are set to <Automatic>. When I click on Automatic I can see all three mail accounts listed in the form My S/Mime Settings (email address). If I attempt to change the security setting from Automatic to one of the account- specific S/Mime Settings the Invalid Certificate message immediately pops up again.
If I click the Change Settings button and then click on the button to choose a Signing Certificate then I get an error message statiing No Certificates Available.
At File/Options/TrustCenter/Trust Center Settings/Email Security when I click on Import/Export Digital Certificates and attempt to Export your Digital ID to a file by clickiong on Select... I again get the No Certificate Available error message.
Any idea how to get Outlook back to working with my certificates?
BTW: I set up my email accounts with certificates and encryption because my wife and I were having a major problem cyber attacks on our PCs and with MITM attacks on our email. I am concerned that my PC may be suffering a relapse...
