Your connection to Battle.net has been lost.

[McPhisto2051]

I just wanted to host some old maps of mine and always got this error...

I tried removing all stuff from the map but the error still existed.
I even tried an unprotected version of my old map and still have the same bug.

After many random tests, I think it's also about path length and folders.

Over 10 years ago i hosted my maps from sth like D:\games\war3\maps\download\own\"mapname"
I found out, that the path has dramatically changed and now has to be sth like C:\Users\YourNameHere\Documents\Warcraft III\Maps\Download\... and so on...
I created a folder OWN\protected and still had the disconnection.
When I tried just the folder "own" with a map without protection it worked for me...
Another Folder Protected in the OWN folder without protection got me back to connection lost.
I switched to a folder PROT in the download folder et voila: it worked again.

So im pretty sure it has something to do with the length or deepth of the folder your map is in (perhaps also the length of your map)

the correct folder and map protection got me back to disconnection again, but at least I know its not my map nor the folder anymore...

 

[McPhisto2051]

First Addition:
looks like your map name also shouldnt have any blank spaces in it...
renaming the map to "1" with protection seems to work.
at least for me its proven.
The exact same name works with "_" instead of spaces...

back in 2018 and before there was never a problem with spaces (and even longer map names)...

 

[Dr Super Good]

There has always been a limit to normalized file path. This limit likely stems from some silly use of statically sized buffers.

Maps you intend to host should always go in the Download folder, and not in any sub folder of that. The map file name should contain only plain English alpha-numeric characters with spaces and be as short as meaningfully possible. If your native locale does not support English alpha-numeric then your map file name should contain appropriate equivalent characters for your locale and you must expect there to be possible compatibility problems with English locale players.