Solved The game asks me for the password every time I exit the game.

Hello and welcome back, @correogomez. I've seen this issue a couple of times in the past decade and pretty much every time it has been somehow related to the user's internet provider and it eventually got fixed by itself sooner or later. Although there are a few similar results on google (some from many years ago too), nobody seems to know the exact cause of this as it's not something common. Normally, this kind of behavior happens when you log in with two characters that belong to one account, at the same time, but in your case you already said you are using only one game window.
I remember you had some issues with your internet provider in the past as well although I'm not sure if you are using the same company now but chances are this is going to fix by itself eventually or in case you have a mobile internet connection you could create a hotspot and use that instead as a temporary workaround.

 

This is what I meant by being related to the user's internet provider (although the old game architecture itself must have something to do with it too) since we are talking about game servers hosted on different continents here and you're having issues with both. It could probably be due to some faulty routing or packet setting that the game's platform doesn't like, as the software is also different from the battlenet one's. If it happens everywhere else but on battlenet then that could be one of the reasons, however, things are probably way more complicated as the google results for this rare weird issue are coming mainly from the official servers which means people have been experiencing this weirdness there as well.
As I mentioned in my previous post, if you got by any chance a 3/4/5G mobile connection then you could create a hotspot and use that as a temporary workaround but first, some very basic troubleshooting that you could try is something as easy as resetting your router by unplugging it for 60 seconds and then plugging it back in, if your provider offers different IP ranges then you should obtain a different routing and you can see if that works for you. Alternatively, you could use a VPN and see if that changes anything for you.
There's no doubt this is a weird game issue and considering you never had it before it will most likely get fixed by itself sooner or later but unfortunately there's not much information about it out there.

 

You are very welcome, @correogomez. By mobile connection, I meant 3/4/5G mobile data and connect to it from your laptop; assuming you are using a laptop or a PC with a wireless card, otherwise this won't work. Check the last alternative I shared in my previous post otherwise.

 

Glad to hear @KindlyChat, but chances are this was the random ISP fix/change I was talking about since you've already told me last week that using a mobile phone to make an access point was working just fine and this was without any compatibility changes. Compatibility changes usually help if the application doesn't start at all. Hopefully they won't be messing up things again in the future.