Creating self signed cert ERROR

Creating self signed cert i am getting this error anyone help me?

Thanks

 

What's the output of

Code:

ls -la /etc/ssl/certs

?

 

I had the following output

 

Can you try

Code:

cp /etc/ssl/certs/dovecot.pem-old /etc/ssl/certs/dovecot.pem
dpkg-reconfigure dovecot-common

?

 

its just returns that there is already one.

just to clarify the only reason i want to do this is so sign the cert off as someone else then localhost.localhost so thunderbird will stop annoying me every time i check my email.