When I enter a wrong password, I get an error.
When I enter the right password, it hangs.
It's in legacy mode. (was working before upgrade)
I can indeed access the sstem as I was using it the day before. The fiver guy says it stuck without user code??
Am I really forced to reset it and loose my config?
No.
You need to be using Winbox 3.27 in non-legacy mode if your RouterOS version is 6.48
You could always try command line access with SSH (or even Telnet).
Sometimes you need to delete the .viw files that Winbox creates in %AppData%\Roaming\Mikrotik\Winbox\sessions