Your local configuration file’s loadComplete() call is incorrect, and so MathJax doesn’t know that the file has loaded, and so waits for the call to be made, and eventually times out. The loadComplete() should be either the full URL (including the "https://", which is missing from yours), or one that is based from the “[MathJax]” root. Since your local configuration file is in the MathJax/config/local folder, I would recommend that you use
MathJax.Ajax.loadComplete("[MathJax]/config/local/mwMathJaxConfig.js”);
in this case.
Davide