dear gromacs users i did simulate zinc and copper ion on human growth hormone protein when i saw my md.gro and md.xtc files by VMD software i found out my system isn,t in the box(cubic) i tried to solve this problem by : trjconv -f md.xtc -s md.tpr -o new.xtc -n index.ndx -pbc mol but there is this problem,again. could you please help me