If you have done an update to 1.0.36, you MUST NOT install the debug version, that is old and less optimized/debugged compared the one included in 1.0.36 FW release. Now, trying to avoid the long procedure to reflash latest IMG FW release and then update to 1.0.36 (best to have an X6 in clean situation), you can extract the app from OTA FW zip (20160413_ZIDOO_X6_Pro_v1.0.36_ota.zip) on a PC. The ZDMC app path is \system\preinstall\kodi.apk Then install it on X6 as usual. Please, don't ask how to do, there are already many discussions/thread about it on this forum.
Hi Sarantos, May I know which add-ons are you trying to install? Because a few weeks ago, I too was facing the same issue and I fixed it by just getting a VPN. I recommend you to get the best VPN for Kodi- https://firestickhelp.com/best-vpn-kodi/
I would be very happy if I could help you here, a few days ago I bought an Amazon Firestick device, then someone suggested to me that you use the add-ons in it, you will get very good results in video streaming, so I gathered some information about add-ons by long researching, I found Kodi-Addons- https://www.firestickhow.com/kodi-addons.html as best options for me because I love to watch live streaming videos in sports. Once you have installed Kodi on fireStick or any other device, you would want to start watching your favorite video content such as Movies, Shows, Live TV, etc.
No need to install third-party addon to Kodi, just install the Cinema HD Repo/add-on to Kodi by Jesus rep. Check out this guide