Unable to connect message almost continuous

Why does my Eufy app continually show:
“Unable to connect to the application server”

I assume the server is the Homebase box. This was originally connected via ethernet not because one camera continually had PLAY problems, cameras are now connected via wifi. Makes no sense to me. Server (& router) are within 35 or less of all cameras. I would have thought cameras would work better with the server connected via ethernet rather than wireless???