MATLAB: Problem to access OPeNDAP data behind https:// urls

httpshttps:// opendapMATLABopendaptroubleshooting opendap

Hi!
I'm trying to access an OPeNDAP server with the https:// handle. I have the R2019b version of matlab. As far as I understand, matlab can't access the file directly because of security reasons(?). But it seems as though sometimes my code works and extracts the variable, sometimes not. See here
>> m=1
chl_A(m)=ncread(url, 'chlor_a', [lonnumber(m)-1,latnumber(m)-1,timeM(m)-1],[1 1 1]); %this code extracts data
>> m=2
>> chl_A(m)=ncread(url, 'chlor_a', [lonnumber(m)-1,latnumber(m)-1,timeM(m)-1],[1 1 1]); %this does not
Error using netcdflib
The NetCDF library encountered an error during execution of 'open' function - 'I/O failure (NC_EIO)'. If the data source was an  OPeNDAP URL,
see the OPeNDAP Troubleshooting section in the Users Guide.
Error in netcdf.open (line 67)
        [varargout{:}] = netcdflib ( 'open', filename, varargin{1} );
Error in internal.matlab.imagesci.nc/openToRead (line 1278)
            this.ncRootid = netcdf.open(this.Filename,'NOWRITE');
Error in internal.matlab.imagesci.nc (line 121)
                    this.openToRead();
Error in ncread (line 61)
ncObj   = internal.matlab.imagesci.nc(ncFile);
and basically matlab does this to the whole data. I have 158 points to extract and it only extracts about 30 of them, for the others the error comes up. Why?
This code used to work when the server was a http:// one. Is there any way to fix it or bypass it?
Thanks in advance!

Best Answer

Hi Sofya
Thanks for the information. I was able to reproduce the issue and I have brought this issue to the notice of our developers. They will investigate the matter further.
In the meantime, can you try upgrading to the latest release of MATLAB and see if the issue persists as I was not able to reproduce the issue in R2020b.
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