Did you place it in the right folder. Since version 4 the orbits files don’t go into just one folder for the year. They go into mission year month folders such as auxdata\Orbits\Sentinel-1\POEORB\S1B\2016\10\
Your product is S1B make sure you have the S1B orbit file and put it into the S1B\2016\10 folder.
I suspect you are using an older version of SNAP. In the latest version, if not found on the server, it will find it in the qc website and get it for you.