Audio Plugin Host error

I’m new to JUCE and following a tutorial. I was able to open the AudioPluginHost.app before and view the available plugins but now the app shows up blank with the loading icon running too long
with a breakpoint pointing to this piece of code

#if JucePlugin_Build_AU
jassert (wrapperType == wrapperType_Undefined || param->getVersionHint() != 0);
#endif
}

and in the error console I get this

JUCE v6.1.6

JUCE Assertion failure in juce_AudioProcessor.cpp:441

Please help as I want to be able to complete each step of the tutorial.