“Invalid API Key. Please verify your API key is valid” Error

OK. I am at the end of my tether. It must be something I am not doing or doing wrong.
Purpose: I am trying to activate my Google API key in the settings menu of the Material design settings.
I go across to Google Search Console to get my key and I get it.
Now I have had a few issues with Googles Domain verification but Google gives you a few options. I have managed to verify the domain using the html file option and later the domain name TXT option so I should be fine now with Material Design. Google itself accepts the API key it gave me and allows me to download the whole fonts.
Google site kit accepts all my API keys. But not Material Design. In Material Design Settings, it does not accept the API key. Comes up with the message: Updates disabled and when I try to activate the API key, I get this message: “Invalid API Key, please verify your API Key is valid”
No matter how many times I go back to Google, it gives me same key and your plugin rejects it.
I am on Windows 10 and I have pasted the key in Note++, used html, javascript file formats. I still get the same results so HELP!

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