Connect chromecast ultra to wifi network issue

Hi .
We use a Peplink for organising network.
Wifi works ok . But we have an issue, can not connect any chromecast devices.
Do you have any suggestions to fix that problem?

Just chromecast devices? That’s weird. They used to complain about connecting to mixed wpa2/wpa3 networks.

What security policy settings are you using? WPA2/WPA3? Try dropping back down to WPA2 and see if that fixes it - then look for chromecast firmware updates.