There is an algebraic loop in your model. The error window also suggested two actions to solve the problem under the title "suggested actions". Apply the first suggestion by clicking the "fix" button.
If the algebraic loop is not resolved, than you will need to add a delay block: https://www.mathworks.com/help/releases/R2020a/simulink/slref/delay.html with a delay of one time-step before the gate input of three-phase inverted.
