You don't need anything under the initial conditions, I asked because the folder was collapsed so I couldn't see what was in the folder.

Another change what would surely increase the likelihood of convergence is if the Acceleration load ramps up from zero to 9.8 m/s^2 over 2 seconds or more. Ramping the acceleration up from zero is much easier to converge than applying it as a Step change at T=0.   You can ramp up by having a 2 step solution, where step 1 goes till 2 seconds, then step 2 ends at 4 seconds.  The acceleration ramps from 0 to 9.8 m/s^2 during step 1 and then is constant at 9.8 m/s^2 during step 2.