If it doesn't solve the issue, please share the model with the modifications that you're working on so I can take a look. I tried to reproduce the issue with the frequency F0 as 28 GHz and the fundamental tones and harmonies that you used, but I wasn't getting the same error.
However, I did get that error "Delay history is too long. Decrease the delay time or increase the time step. ''" when F0 was set at the default value.