Hello John,
This error occurs when your model has some algebraic loops where the some signal loop could create a circular dependency for example expecting an output at the same time as the input. Please refer to the following page to know more about algebraic loops and ways to resolve it. https://in.mathworks.com/help/simulink/ug/algebraic-loops.html
Also, from the warnings, I can see that few domains require their own domain reference blocks which could also result in the algebraic loops error. Please refer the following page to understand better about grounding rules.
