Yes - you are trying to read the asis set from the LCModel website, right? These are, for a weird inexplicable reason, encrypted (You can validate that it’s encrypted if it has a negative BADELT entry).
We have a version of op_plotspec in Osprey that breaks this encryption (which was possible after Provencher released the LCModel source code); you can find it behind this link. Note that our FID-A version reverses the fft sense and the frequency/ppm axes and is therefore not compatible with native FID-A (see also FID-A simmulation code - Data Processing - MRSHub Forum); you’ll need to only have one version in your MATLAB path.
Generally, I would strongly recommend to not use the basis sets provided on the LCModel website. They are based on phantom acquisitions (not simulations) and no one knows the exact acquisition parameters, so they will likely not be a good match for your sequence.