Starting from 11.09.2013 it is no longer possible to automatically install access certificate through old DigiDoc Client software (version 2.7.11 included).
Access certificate gives access to Sertitiseerimiskeskus's validity confirmation service which is necessary for digital signing in DigiDoc Client. Old DigiDoc Client versions are no longer supported and their usage will be restricted. Additional information can be found here.
If you are still using the old DigiDoc Client software, then please update to the latest officially supported digital signing software found at installer.id.ee website.