Receiving errors about singularities in my Simulink model

If I set all of my configuration parameters to 'auto' and run my model I get the following error, always at time = 1 second.

"Derivative of state '1' in block 'Homework_3/Transfer Fcn' at time 1.0 is not finite. The simulation will be stopped. There may be a singularity in the solution. If not, try reducing the step size (either by reducing the fixed step size or by tightening the error tolerances)"

I've experimented with different time steps while the solver is set to 'auto' and I am also getting the same error.

I've tried commenting out all of my scopes according to a similar Matlab question and that didn't help.

If I set my Solver to 'ode15s' as recommended by another Matlab question the time step is set absurdly small like 10^-10 and I get a similar error if I try to increase the step size. The code is provided and comes from an in-class example. I've verified with the professor that the blocks are correct but he couldn't come up with any solution to the error either.