Shelly device is making fun of me

Hello Homey community

I have a problem adding a Shelly device and hope for your help.

I have previously had my Shelly Dimmer 2, on the Homey system (Pomey Pro 23), without problems.
But after installing a new WIFI system, I have had problems.

I have removed my Shelly device from the Homey system, and now can no longer add it to Homey again.
I have made sure that all devices in my network run on 2.4 ghz wifi and that all devices that are added to the wifi are assigned their own fixed local ip address.

I have tried removing the device from Shelly’s app and adding it again. with that does not provide the solution in terms of adding it to Homey again.
I have also factory reset the device. That didn’t help either.

Can you help?

Did you have a look at the Shelly app specific topic and specifically the first post in the topic?

There is a section about common troubleshooting tips.