Use Beams:frameType=1 (center-of-mass) instead of Beams:frameType=3 (fixed-target)

There is an issue in Pythia 8.3 (since 8.3.10 I believe) where you will face error messages/aborts when simulating collisions at the highest energies using the fixed-target beam setup via Beams:frameType=3, Beams:pzA and Beams:pzB. Spotted in /master/corsika/detail/modules/pythia8/Interaction.inl, line 66-70:

// Set up for fixed-target collisions.
pythiaColl_.readString("Beams:frameType = 3"); // arbitrary frame, need to define full 4-momenta
pythiaColl_.settings.parm("Beams:pzA", eMaxLab_ / 1_GeV);
pythiaColl_.readString("Beams:pzB = 0.");

The Pythia authors are aware of this problem and an issue is open on their gitlab for it to be resolved. In the meantime, it is recommended (in the main425.cc from the Pythia 8.3.12 release) to use the Beams:frameType=1 along with Beams:eCM to set up the equivalent center-of-mass energy of your original fixed-target collision.