E05 - Unknown Smartcard
Common reasons for this error
The smartcard in the decoder is not recognised, possibly because it's invalid.
Suggested fix
Make sure you are using a valid smartcard for your decoder and insert it properly into the smartcard slot.
If it's already inserted but not recognised, remove it gently, clean it with a dry, soft cloth to clear off any debris or fingerprints, and then re-insert it. This should help the decoder recognise your smartcard.