CDO

Im having some issues converting from netcdf to grib2 format
usage : cdo -f grb2 selgrid,1 INFILE.nc OUTFILE.grb

I get the following
GRIB_API ERROR : concept: no match for shortName=sig_wav_ht
Warning (gribapiDefParam) : grib_api: No match for shortName=sig_wav_ht
gribapiDefLevel : Changed zaxis type from generic to pressure
GRIB_API ERROR : concept: no match for shortName=mean_wav_dir
Warning (gribapiDefParam) : grib_api: No match for shortName=mean_wav_dir
GRIB_API ERROR : concept: no match for shortName=mean_wav_per
Warning (gribapiDefParam) : grib_api: No match for shortName=mean_wav_per
GRIB_API ERROR : concept: no match for shortName=swell_ht
Warning (gribapiDefParam) : grib_api: No match for shortName=swell_ht
GRIB_API ERROR : concept: no match for shortName=peak_wav_per
Warning (gribapiDefParam) : grib_api: No match for shortName=peak_wav_per
cdo selgrid: Processed 2067285 values from 5 variables over 17 timesteps. ( 0.08s )

the grib2 is created, i can use map, sinfo, etc with it, but cannot open it in any other grib viewer (Ugrib, grads, etc.)
also, my initial .nc file had five variables, the new .grb file has 1 variable with all the data

any help would be great
Thannks