When I click on the download button nothing happens, what to do?You wait but nothing happens, no file is downloaded, possibly after a few minutes of waiting you receive an error message of the type "Connection timeout" or "ERR_EMPTY_RESPONSE" or other messages according to your Internet browser.
In fact, the downloads from Rikoooo are sent from another local server on port 8888 (ex http://download.rikoooo.com:8888) this for a better stability of downloads especially with files of several Gigabytes.
The problem is that the firewall of the router (ex Livebox, Freebox, Neufbox) of certain users is configured to refuse the port 8888 (and also the port 8080), to know if you are in this case, go to Simviation.com and download any file at random, if the download does not start (like at Rikoooo), then you are among those small percentage of users whose router blocks port 8888 (and 8080 for Simviation). Those ports are normally used for the web interface, streaming, and HTTP, therefore, it's safe to open.
You must connect to your router (ex Livebox) and add a rule that opens the 8888 TCP / UDP port.
Here are links to some articles in English that explain how to open your ports, do not hesitate to do your own research on Google using the name of your Internet service provider as a keyword.
Link to Youtube videos with dozens of tutorials (add your Internet service provider as a keyword)