Translate Site Interface 9.1.2

Hi I am using Concrete cms version 9.1.2 and I have following all the steps as described from help session “Translate Site Interface”. There is no any error when I am saving the translated sting but unfortunately string does not change in the site! In database it is changed but in the site not! I have proceed all the times clearing the cache.

When I was installed the 2nd language (Greek) a file was created under: application/languages/el_GR/LC_MESSAGES/

Then when I have follow help, I have created the folder application/languages/site and some files created under this folder and el_GR.po but it seems that the application reading the strings from the 1st file application/languages/el_GR/LC_MESSAGES/

Any help please?