Magneto Quasi-static simulations stop


I am running Magneto Quasi-static simulations for some portions of realistic body models. I use Biot Savart simulations as source files. Resolution is 1.5 mm with total number voxels is around 45 - 50M. Simulations usually finish without errors; however, they got stuck at either 0% or 99% without clear error log. This error is more likely to occur when I submit 3-4 long simulations at the same moment using batch function. Even if I submit many simulations simultaneously, sometimes first one or two finish successfully and error occurs in the middle of the query. Even if I submit a single simulation, it can still happen. In the console, I just see "The solver process returned an error code: " without any error code. In the solver log, it says " EM-Low-Frequency simulation finished with errors." at the end of line. Therefore, I have no clue what is going on and it really slows down my simulations. I would appreciate your help to overcome or at least debug this problem.

Thank you.