Unable to upgrade Networker VE from version 19.3 to 19.4

Hi all,
From Networker Installation Manager, I can't upgrade from 19.3.0.6 Build.212 (Virtual Edition) to 19.4.
After successfully validating password of admin account, install goes in timeout when trying to validate root account password (see capture 1 and 2). Note: connecting in SSH with admin account (then with root) is OK.
Any idea how to fix it?

Thank you in advance.
KR,