Assertion failed: ; Condition: realGrid_ ;Bad (null) input real-space grid

GROMACS version:2020.4-MODIFIED
GROMACS modification: Yes/No
Hey everyone, I am a newbee for Gromacs. I am trying to run the simulation for my polymer. I am planning to solvate it after I am successful running the simulation with only the polymer in the box. I prepared the file and run the minimization, equilibration, and production. But it fails and the slurm file said :Assertion failed:
Condition: realGrid_
Bad (null) input real-space grid

I am wondering what’s going with my file. The attached file all my input file for the simulation. Any help would be appreciated! Thanks ahead!!
PPLn_question

This the google drive link in case the above one doesn’t work.

Hello Junbao ! Have you solve the problem? I face the problem too

it’s not my first time to run the files. But this time the solvent molecules (THF) i used, i haven’t tried before. so I tested another new molecule (like DMSO) as solvent, which ran sucessfully.