Connecting with mqtt broker failed

Since yesterday, my Sonoff Tasmota 4ch devices have no contact anymore.

When I call the 4ch devices with ip, I can still operate them.
However, in Homey Pro (early 2019) v 8.0.8. It does not work.

I use Mqtt broker v2.0.0 and Client v3.0.0 from Menno van Grinsven.

directed to ip homey (still correct) and gate 1883, as on the Sonoffs themselves.

already restarted homey, apps, uninstalled-installed apps, …

Anybody who can help?