it's not a problem with esxcli command, update procedure and VMware's repository address. It's a problem with routing and ESXi host's vmk0 IP address exposure.
Contact with your OVH provider to assign your host external address or configure a NAT/PAT rule to make the host able to properly communicate with the repository.
If wget responds with this it will be ok.
[root@esx1:~] wget http://hostupdate.vmware.com/software/VUM/PRODUCTION/main/vmw-depot-index.xml
Connecting to hostupdate.vmware.com (23.212.228.56:80)
vmw-depot-index.xml 100% |**********************************************************************************************************************************| 605 0:00:00 ETA
Regards