Segmentation fault in a mixture (core dumped)

I am using gromacs 2020.2. I want to build a setup like in the figure attached here:

First I equilibrate a box of polymer/ion/water (in the middle of the box and blue area) and then added two water boxes on both sides of the relaxed polymer box (blue region) and finally justified box size based on the system size. The simulation procedure is successful in minimization. But, on nvt level I face to this error:

Step 3, time 0.003 (ps) LINCS WARNING
relative constraint deviation after LINCS:
rms 4667552256.000000, max 644798283776.000000 (between atoms 6824 and 6829)
bonds that rotated more than 30 degrees:
atom 1 atom 2 angle previous, current, constraint length
81 85 90.0 0.1080 0.1860 0.1080
89 94 90.0 1.7146 1.8413 0.1080
92 97 51.2 38.5901 145.6929 0.1080
Wrote pdb files with previous and current coordinates
Segmentation fault (core dumped)

I changed the time step and checked the topology file tens of times but the error still remained. What is the main problem?

Thanks in advance

What was the outcome of energy minimization in terms of Fmax and Epot? If your first MD after minimization fails after 3 steps with such insane values, it wasn’t stable to begin with.

Dear Lemkul

I found the reason. My system size was very large. I decreased the number of water molecules and the problem is fixed.

Thank you