Hi everyone.
I’m hoping that someone can help me figure out a problem I’m having with the installation of addons on both a brand new ”Mecool” tv Box, and a brand new Firestick 4K Max. Both WERE running with Kodi 19.3 Matrix (I’ll explain the “Wear” a bit later).
The issue I’m having is that when I’ve tried to install these addons (Diamond (including the Diamond Build) and “The Crew” specifically), although the installations seem to be done properly, and I’ve gone into the “Install from zip file” and get the “Addon installed” message. Then, I go into the “Install from repository” and installed what I want from there, and it tells me when each item has been installed”. From there, I return to the Kodi main screen, and all of the icons for those items I installed from the repository are showing, and this is where the issues I’m having start. I’ll use “Sportsdevil” as an example. When I click on the icon, of course I should be able should be able to launch the addon, or at least show other things that need to be clicked on ( for example, sports categories, or various sports networks (i.e. Fox Sports, ABC Sports, etc.). Once you select the network you want, it rshould launch so that the content can be watched. However, and even though my settings have been setup to Allow “Unknown Resources”, when I click on what I want to view, there are NO files available for viewing. 
For example, as I mentioned, I installed the “Diamond” addon, but when I click on it, all I see on the page that opens are “Categories” and “Next Page”, you can click in one of these all day, and it just keeps on returning to that same page. I’ve done the very same installation for “The Crew”, and the only difference is, even though I’ve completed everything that I want installed, the icons for this addon are not showing up at all.
I mentioned before that both the box and the stick “WERE” running on Kodi 19.3 on both the box and the stick. However, I thought that possibly these two particular addons, may not have been adapted for the 19.3 Kodi version, so I uninstalled it and installed Kodi 18.9 instead. Unfortunately, I’m having the same issues.
I know that this might be quite confusing, so if you need any clarification on anything just let me know.
Any assistance in helping to figure out what might be the problem would be greatly appreciated. Thanks for reading this long message.
Cheers!!