Mac with OS10.15 no longer connects to dashboard

Hi,
I recently bought myself a EX4100.
It worked well, …for a while !
Suddenly I am no longer able to get into the dashboard, although the ex4100 is still visible in Finder.
So, I can still use the ex4100, but I cannot get into the dashboard anymore.
I tried all resets and reboots of both mac and router, but without any results.
Is someone able to help ?
Thanks !

Macbook Pro 13" with Mac OS catalina (10.15)