Common Shopify connection FAQs and Troubleshooting
How do I fix a "OAuth error invalid_request: The redirect_uri and application url must have matching hosts" message?
When connecting to Shopify you may get an error "OAuth error invalid_request: The redirect_uri and application url must have matching hosts" which will look something like this:

This means that your redirect URL and app url are not correct or there is a mismatch.
Review steps 6, 7, 8 and 9 of the setup article How to integrate your Shopify account with Trove to ensure that the values are correct.