Is impossible install package flashplugin-nonfree. Result is "Connessione a fpdownload.adobe.com (fpdownload.adobe.com)|104.106.117.189|:443... connesso.
Richiesta HTTP inviata, in attesa di risposta... 404 Not Found
2017-08-27 21:37:52 ERRORE 404: Not Found.

ERROR: wget failed to download https://fpdownload.adobe.com/get/flashp … _64.tar.gz
More information might be available at:
  http://wiki.debian.org/FlashPlayer"
What about this ?