The current setup of gcompris.net is not completed correctly in the past it seems. I can see we have setup our nameservers correctly in the past, but you have not changed the nameserves at OVH.
We can do 2 things:
a) we remove our config and you keep maintaining the domain configuration at OVH.
b) you point the domain to our nameservers.
If we choose b) we need to double check if our configuration is still accurate and then I can give you the correct nameservers you can configure in OVH.
Let us know what you prefer.