If you are not a developer, it is a bit difficult to try to figure out what’s causing the issue.
Unless you want to do a Zoom call where we could go through the debugging process?
But the first thing I would check that the REST API is working.
Could you check the steps mentioned on this page and see if any of them apply to you? https://redirection.me/support/problems/rest-api/
And the second thing would be checking the browser developer console for errors.
On the plugin page, if you are using Chrome, you can right click on the page and select “Inspect”. On the bottom of the screen there should be a new window with several tabs. Select the one that says “Console” and write down any messages there in this thread.