If your epoch time is in milliseconds instead of seconds, remove the last three digits before passing it to
date -d
:
$ date -d @1455086371603
Tue Nov 7 02:46:43 PST 48079 #Incorrect
This gives incorrect data. Remove the last three digits.
$ date -d @1455086371
Tue Feb 9 22:39:31 PST 2016 #Correct after removing the last three digits. You may remove and round off the last digit too.