Unable to login via winbox after upgrade v6.45.1

Hello,

so i upgraded a couple hundred of my Routerboards yesterday
(v6.45.1) after upgrading the packages, I also upgraded the firmware and performed a final reboot on every Routerboard.

Everything went fine, and everything was working,
however, one device (RB3011) reports “ERROR: wrong username or password” when i try to access it via WinBox (3.18)

The funny part is:
I can access this Routerboard with exactly the same username and password via WWW or SSH.
I even get the failed login attempts in the ssh cli:

07:42:48 echo: system,error,critical login failure for user admin from 10.48.99.13 via winbox

(Yes, i checked for typos and yes i am using a password manager to copy my credentials)

I tried to reboot the router, i also tried a hard reboot with cutting the power,
i checked the installation → OK,
but nothing seems to work.

Winbox service is enabled:
service.PNG
Firewall is set up correctly:
firewall.PNG
any clue?
thanks guys!

edit: i just tried to connect via Mikrotik Android App and i get the following log entries:

user admin logged in from 10.48.99.22 via winbox

However, the app is stuck at “connecting…” screen.

After contacting MikroTik Support and providing them access to the router,
they noticed a bug in the winbox client.

Mikrotik Response:

We will release a new Winbox version with the fix for this problem as soon as possible.

edit: WinBox v3.19 ist released and the bug is fixed!
Thanks!