Hi Ininfinity,
I think some troubleshooting might be useful to find where the blockage is.
They have different versions of their software on their website listed here, including a no-download version:
https://www.winamax.fr/en/play-poker
Do other versions of the software work for you on your home PC/home network? Can you use the no-download version on your PC? Can you use the mobile version on your mobile device on your home network?