CDO

I am trying to remap GLEAM3.6 data and am running into an issue when using any remap- function. The error I am getting is cdo(1) remapbil (Abort): Unsupported generic coordinates (Variable: SMroot)!

I've looked through the forums and wasn't able to identify why my issue was any different than anyone else. I've included all the information that appears to be needed to diagnose something. I've also included the smallest possible dataset. Thank you for any advice anyone can provide.

#####################################sinfo
File format : NetCDF4 zip
-1 : Institut Source T Steptype Levels Num Points Num Dtype : Parameter ID
1 : unknown unknown v instant 1 1 1036800 1 F32z : -1
Grid coordinates :
1 : generic : points=1036800 (1440x720)
lon : -179.875 to 179.875 by 0.25
lat : 89.875 to -89.875 by -0.25
Vertical coordinates :
1 : surface : levels=1
Time coordinate :
time : 366 steps
RefTime = 2000-01-01 00:00:00 Units = days Calendar = proleptic_gregorian

#####################################ncdump -h
netcdf SMroot_2000_GLEAM_v3.6a {
dimensions:
time = 366 ;
lon = 1440 ;
lat = 720 ;
variables:
int time(time) ;
time:units = "days since 2000-01-01 00:00:00" ;
time:calendar = "proleptic_gregorian" ;
double lon(lon) ;
lon:_FillValue = NaN ;
double lat(lat) ;
lat:_FillValue = NaN ;
float SMroot(time, lat, lon) ;
SMroot:_FillValue = -999.f ;
SMroot:standard_name = "Root-zone soil moisture" ;
SMroot:long_name = "Root-zone soil moisture from GLEAM v3.6a" ;
SMroot:units = "m3.m-3" ;

// global attributes:
:Dataset = "Global Land Evaporation Amsterdam Model" ;
:Version = "3.6a" ;
:Authors = "Hydro-Climate Extremes Lab (H-CEL)" ;
:Institution = "Ghent University" ;
:Contact = "info@gleam.eu" ;
string :Reference1 = "Martens, B. et al. 2017: GLEAM v3: satellite-based land evaporation and root-zone soil moisture, Geoscientific Model Development, 10, 1903–1925, doi: 10.5194/gmd-10-1903-2017" ;
string :Reference2 = "Miralles, D.G. et al. 2011: Global land-surface evaporation estimated from satellite-based observations, Hydrology and Earth System Sciences, 15, 453–469, doi: 10.5194/hess-15-453-2011" ;
}

#####################################.grd file #

1. gridID 1 #
   gridtype = lonlat
   gridsize = 1593
   datatype = float
   xsize = 59
   ysize = 27
   xname = lon
   xunits = "degrees_east"
   yname = lat
   yunits = "degrees_north"
   xfirst = 235
   xinc = 1
   yfirst = 50
   yinc = -1
   scanningMode = 64