After I did fresh install of Ubuntu 15.10 I had to setup GPG encryption with Evolution again and it is not working properly (prior to fresh install it worked fine on Ubuntu 15.04
After I select Option > GPG encrypt I am getting this error:
Because "gpg: CEF41E5C: skipped: unusable public key gpg: [stdin]: encryption failed: unusable public key ", you may need to select different mail options.
How to fix this error? thanks in advance :)