When i try to log in to battle net i get this error and when i go for offline mode and try to run the game by manually entering user and pass i get BLZ51901016 error.
Tried this guide https://us.battle.net/support/en/article/13875 but didn’t work. Network reset. turning firewall and anti virus off also didn’t work. Several router reset and uninstall/reinstall battle net app also didn’t work. My ticket to customer support didn’t solve the problem and so reinstalling the game. Tried with mobile data and didn’t work. setting DNS to 8.8.8.8 and 8.8.4.4 and change region didn’t work. Windows time and date is correct and only when i use VPN i can bypass this headache which is not the real solution as we all know. I really appreciate if anyone know how to fix this and give me a solution.
Thank you
I had “world server is down”, now I only get disconnects but possible reason is world servers are down.
[edit]
This looks like a more serious problem because I can’t also login neither to Classic or Cataclysm Classic (they properly return “world server is down” message).
If “world server is down” is related to realm status mine is up. check for your realm here https://worldofwarcraft.blizzard.com/en-us/game/status/eu. I can only log into the game with VPN.
I don’t think is related to “server is down” because login server and world server might be different instances.
It is related to some ISP’s. On my main connection i have World server is down but on mobile connection it’s all Ok.
Read my previous comment. I speak from IT experience, login server works (I am logged to battle-net just game server is not responding). This is not ISP related either.
I was thinking about this and tried with mobile data but same problem exist. I saw another post mostly with people from Sweden with Tele2 but i’m not from there and not using Tele2.
It’s regional problem …
I’m on discord with friends from all around Poland … but only 2 of us (from Pomeranian, near baltic sea region) got the same issue, while other do play with no problems.
The internet in general works fine.
We can log-in to other Blizzard services, for example play Overwatch.
But just can’t get into WoW - sometimes stuck on connecting to Login server, other time I get to character selection screen but on loading to get get stuck and then World Server is Down.
Regional or not, not happy to be where I am. I’d like to have ETA on this problem (and definitely a game time refund). I was able to play but with issues, so I had to log off because I couldn’t progress, you know what I mean, that is the world servers were not updating. And I know internet works fine.
I have reset the interface. I have restarted my laptop.
I can log in to the Battle.net app just fine. However, after that, I can’t log into the game. I either get stuck endlessly on the login screen, or - rarely - I get the ‘World server down’ error. Sometimes, I get logged out entirely.
Oddly enough, there is but one character that I can log in without problem - a 10 level bank alt in Stormwind. I’ve tried like 15 other characters, both in Stormwind and across multiple zones and none were able to log in.
EDIT. 20 minutes later I can’t log in on that single bank alt anymore:(
Eu.*battle.*net is down as well, can’t open any support article.
I feel you 
When I started to get issues I was not able to heart to Stormwind or teleport anywhere, instance error. But I believe that is already known, we just would like ETA. My rested exp is gone QQ. And I am here on forums 
Wholehearted welcome from returning player, Had no issues for 3 weeks I know this will also get fixed. Just wanna know wheeeeen
Hi, i have the same issue. From an internet search it seems that its something with the interface and resolution of the game. I don’t know what to do to fix it.
I used to have huge latency issues, related to bad routing aka packet loss, I managed after few weeks to find a solution, ever since each time I sit down to play the game, I have opened in background a ping command to one of the servers I know that I am connected while playing. Sometimes when I see a lag in game, and I tab out to see if there is server replay, and there is not, I know it’s packet loss and I just sit tight and wait few seconds. It’s all playable, not like I and many others used to have… Other times, server is responding, so I know it was just some minor lag in the game, that can happen. Well, today when I did that, the server is not responding at all, but somehow I managed to get into character and loading screen, but here I was stuck.
Finally after few tries I got in to the game, all works fine, but I can’t enter the raid I was gonna do now. When I get summon it says transfer aborted: instance not found, also can’t enter there on foot. So yeah, no group content for me right now. Hopefully its fixed by tomorrow, it’s weekend.
I have the same issue since ~8 PM Burning Legion
Same.
Server: Burning Legion
Country: Poland
ISP: Vectra
I’m tired or trying to blame players or their ISP’s or hiding real issues. It has been 12 hours the game is unplayable because world servers are not updating and they can’t create additional instances. Please after you fix it take preventive measures for this to not happen again any soon. US servers work fine, you have no excuses.
You made awesome expansion, but I want to play it, its that time of the year.
Love you all but I am mad.
Good morning , having the same issue since last night.
World Server down.
Loading times are taking for ever.
IF i manage to get in game , the character keeps on realoding to the same spot in game nothing works.
Good morning , having an issue since last night.
It appears to be after the latest Battle Net app update.
Games take very long to launch.
If i manage to get to the character screen the after loading i get World Server down.
Loading times are taking for ever.
IF i manage to get in game , the character keeps on realoding to the same spot in game nothing works and i see a message in chat " Transfer failed " something like that
Good morning , having the same issue since last night.
It appears to be after the latest Battle Net app update.
Games take very long to launch.
If i manage to get to the character screen the after loading i get World Server down.
Loading times are taking for ever.
IF i manage to get in game , the character keeps on realoding to the same spot in game nothing works and i see a message in chat " Transfer failed " something like that
A solution is known I believe, we need to know how long will it take, do maintenance if needed and inform your loyal customers 
I hope it wont take entire week, would be sad to wait until Wednesday, as it happened historically and we survived but not good perspective