Error 404 after plugin installation

I’d like to buy the pro version of your plugins pack, but before doing it, I need to make sure your map routes plugin can actually work on my site.

When I go to dashboard https://www.myfamilytrips.com/cm-maps-routes/routes/index/ or try to create a new route, I keep getting Error 404 Page.

I did everything you suggested in the troubleshooting section – permalinks checked, rules flushed, google maps api setup and inserted into the plugin.

Any ideas?