Shopify Connect and Sync settings always “disconnected” with error message

Regardless of whether I enter my API key and other pertinent information, I still receive an error message when I attempt to sync shopify and wordpress:

Success! You’ve finished disconnecting your Shopify store from WordPress.

No route was found matching the url and request method while calling rest_no_route. Please clear the plugin transient cache and try again. Error status code: 404

What should I do? My host increased my php limits and this still does not solve the problem.