Don`t get "Authorise a new connection" Window/Popup

Hello,
I using the Kee-Plugin since years and everything worked fine for me and on Win 7 it does what it shoud. But, on Windows 10 , in Firefox I get the Kee-Autorisation-Tab, but I don`t get the “Authorise a new connection” Window/Popup.
Any suggestions?

Windows 10 Home, Version 1903, Build 18362.356
KeePass 2.43
KeePassRPC 1-9-0/2345
Firefox 69.0.1 (64-Bit)