Replacing surrounds

I’m replacing my Era 100’s as surrounds with Era 300’s.

I think I’ve mistakenly selected remove surrounds in the app. The 300s are on the system, in the same room, but not paired as stereo speakers (I think).

When I try to add them as surrounds it goes through all the motions but then stops and says there was a problem connecting my surrounds.

I can’t a way of removing them and starting again.

Has anyone any suggestions?

Many thanks, Dermot