"Token must be service access." error when trying to generate a storefront access token

[HeroicEv]

I'm trying to make a post request for a storefront access token and I got this error. From looking around in the posts I see that my access token may be one of 3 different conditions, but I don't know which of them it could be. I was following the authentication tutorial in "Build a shopify app with Node and React". Could anyone let me know what the problem with my access token is? 

AppID: 4300205

StoreID: 46347124890

The access token was generated today on 10/10/2020.

Thank you.

[YaketyMatt]

Hi,

The access token is within your app. So locate the app screen in your store's dashboard and click on the link, there you should find your key/ token. Good luck, and let me know how you get on!

[HeroicEv]

I believe that's only the case with private apps, but the one I'm making is a public one. Sorry for not mentioning that before.

[YaketyMatt]

I've just had another read of your initial question and realised that you are in fact making a request for the token.

The solution in this case:

https://community.shopify.com/c/Shopify-APIs-SDKs/Error-quot-Token-must-be-service-access-quot-when-...

..was to omit the access_token parameter when making the request. Have you done that already?

[HeroicEv]

I have left it omitted when authenticating, but I still received the same error. I was hoping that an admin or staff could possible determine the problem like in the post you shared because nothing seems to stand out in my code.