Hey there,
I looked over the account and it is currently restricted until July 3rd.
Diablo II actively prohibits proxies or VPNs and connecting with one active will result in being temporarily restricted from classic Battlenet. If you are using any proxies or VPNs it is vital that you disable them when attempting to connect to our classic servers.
Connection to Classic Battlenet can also be restricted if you play from a commercially provisioned IP. This is generally business, public or university based connections. We recommend playing only from Residential provisioned IPs.
Finally this also includes cloud services. If you try to connect using a cloud service the account can be restricted.
This restriction lasts 2 weeks from the last attempted login with the restricted IP.
Please note if you have been restricted due to cloud, proxy, VPN or commercial access usage, this restriction will persist even if you switch to a normal connection type. We cannot remove this restriction and it must be allowed to expire before you will be able to connect again.
Please note this is not intended as a punishment. Due to the age of the service these types of connections are blocked to protect the security and stability of the service.
Once your restriction ends you should be able to login normally from any residential provisioned ISP.
If you are still unable to connect to any gateway after July 3rd, reply back to this post with the details of what you are seeing including any specific error messages.