In general, it is recommended to set FirstModSize larger than ScalingModSize, see other posts on the forum for the meaning of these moduli: Setting security parameters according to 128 bit security (very small CKKS scaling factor) - #5 by ypolyakov, What is the differences among firstModSize, scalingModSize and scalingFactor? - #2 by Caesar, EvalAdd does not add in some cases - #7 by ypolyakov.
This is the same issue as in Crashes with specific parameter setting in CKKS, since there is currently a missing check for equality of the different moduli. We are aware of it and an issue has been created.