Single line diagram measurements, Simulink

Hello, I've tried to make measurements on a single line diagram (3-phase) with a sensor but when I run the simulation I'm met with a model warning/error in the diagnostic viewer: "First solve for initial conditions failed to converge. Trying again with all high priorities relaxed to low.". I'm not sure what the problem is or if there are better ways to do measurements on a single line diagram. Thank you for your help in advance.