How do I fix "Please log in using your Shop account, not your main account."

I apologise that terms set by Shopee is a little confusing,

• "main accounts" are the accounts that support multiple shops.
• "Shop accounts" can login to just one shop.

The app requires the shop account because it's the only account that Shopee will let us use to retrieve the token needed to know that you've authorized us to allow access to your Shopee store.