i keep getting an error i just installed diablo 2 and it says disconnected from battle.net please reconnect when i try log into battle.net
Are you by chance using any sort of VPN software (standalone or part of antivirus suite), or did you try to play while on a business-grade internet connection?
i dont think its the internet cuz i think my internet is a business but my friend plays it in his hotspot and when i tried to connect to the hotspot it doesnt work either idk how to check vpn
Business class internet connections are not allowed to play on Battle.net through Diablo 2. I’m afraid you have likely gotten a two-week restriction from Battle.net on Diablo 2 as of the last time you tried connecting through the business class service provider.
Unfortunately the two-week business-ISP restriction is tied to your Blizzard account, so it doesn’t matter if you try to play on a different connection or even use a different set of game keys on the same Blizzard account, you’ll continue to see the “disconnected from Battle.net, please reconnect” message until the two week restriction runs its course.
Only play Diablo 2 on Battle.net while using a residential internet service provider, and do not use a VPN service while playing.
Sorry to bring the bad news. 
Where is it defined whether or not an internet connection is “business class”? Is this done at the provider side or is Blizzard making this decision somehow?
Telenet is one of the biggest internet providers in Belgium and all users connected via Telenet seem to be having this issue on all D2 gateways including open Bnet… and not just for 2 weeks.
This would be something that is decided by the service provider, mainly at the time of purchasing your internet service package.
Blizzard can tell if it’s business class by your route name on your public IP address. If you run a traceroute to www.google.com and your first hop shows up with ‘biz’ in the name, it would be automatically seen by Blizzard as a business class internet service. This of course is just one example of how they can identify if it’s a business class service or not. There are other ways/different key words.
An example traceroute hop being:
001-002-003-004.biz.exampleisp.com [1.2.3.4]
If Blizzard has told you that your home internet service is business class and you wish to get that changed to residential class, you’ll need to get that sorted out with your service provider.
Side note: It’s not a good idea to post your specific issue on someone elses thread, especially one that is old like this one. In the future, it’s best to start your own thread.