After cpu time hits 8128 seconds my calculations stops

I'm new to Linux and for my bachelor thesis I'm using it in order to calculate properties of materials in physics, therefore heavy calculations are involved. I've noticed that whenever Cpu time hits 8128 second ALL of my calculations are shut down and the code is like this: - pw.x is the program that takes an input file in order to start calculations (diaginalize matrices , find eigenvalues, stuff like that); - Example.in is the input file for instance ; - The program gives me back Example.out The line of code in terminal is : mpirun.openmpi -np 8 pw.x Example.out $ And when I type: tail -f Example.out to see my progress I can see that the program gives me back the time spent by the CPU in doing calculations. When this time hits 8162 seconds everything stops, even if I press via terminal "top" I cannot see the pw.x programme running :( Can you please help me?