Communication with the server failed

Good morning, after a bad installation of dynamics nav 2015, the EDP manager has made a restore of the previous version and from that moment the web client after the login with Windows credential displays the operation buttons but doesn't work. when I press one of the buttons displays a message "communication with the server failed". I've already reinstalled IIS, the web client and the ssl certificate (not self signed). Everything seems correct, but the web client still throws the error. Any help is really appreciate.
Thanks