Here my bet:
You set the tmp folder to use the OVH one, which is not accessible from web navigation.
You should set the tmp directory inside your web directory.
normally, you should fix that by changing the apache conf. But you can't do it on a OVH mutualisé.
How is that you have simlinks in tmp ? Normally, by default, asset manager copy the assets. There is a special setting to force it to symlinks.