wow dude how do you not know this by now...
you are ip restricted, bnet is fine. you made either too many games, did not configure your delays in your leader / follower config correctly or sent malformed packets.
I can give you my leader follower configs if you message me its very stable. as for malformed packets i was attempting to open stash from anywhere in town but i got too far away from the stash and attempted to open the stash and slient exited the game then got hit with a 15 day ip restriction.
other offenses that can cause an ip restriction can include offensive speech in game. i remember a player was talking about "pride" and i called him a future aids victim and told him to get off the server. around an hour later my account got kicked from bnet for 3 days + bliz muted that set of cdkeys for 30 days so blizzard does restrict for chat and this is somewhat of a new development in that it has been this way for about 8 years or so. i just switched cdkeys with my injector and allowed the keys to rest and the chat was restored after 30+ days while i chatted on the clean set during the cool down.
now your ip + accounts + cdkeys are tied so using another fresh ip will re-restrict the new ip. you will need a new clean set of cdkeys and ipv4 residential proxy then you can log into any account and continue playing.
if you had used a vpn when connecting the window would just not even move it would be a solid error. the fact it attempts to connect then give an error of not responding shows you: either too many games, did not configure your delays in your leader / follower config correctly or sent malformed packets. now i would get this bullshit error at least once per ladder season so i would have 15-25 days of down time. what really helped me avoid this is a solid leader follower configs and fixing your internet. even if your configs are correct but you have high packet loss blizzard is very sensitive to characters dropping from games and this too can cause restriction. you have 2 solid ways of fixing your network. i run a fully wired cat6 network with switches and have zero packet loss, you can also use wifi6 and make sure your wireless card is very near the wifi router as with distance will come packet loss and retransmission.
so you are looking at 15-25 days of down time. sometimes i have gotten this error before with my chat fully disabled and it only lasted 3 days. most restrictions happen at the start of a ladder or just before a new ladder due to excessive games made. there is nothing you can do but wait it out and check your network and wire everything. i have not had a restriction now in 3 years.