I am unable to decrypt my own encrypted emails

I can digital sign an encrypt emails to recipients that I have their digital signatures for. I am unable though to decrypt and read emails that I have encrypted. When I navigate to my Sent Folder emails that I have encrypted and send show the "SMIME.p7m" file. I also get the same "SMIME.p7m" file when I send myself an encrypted email. I am able to decrypt emails that are sent to me from others.