Era 100 - connectivity issues

Hi

we have 1 Era 100 in the living room and 1 Era 100 in a TV room. Both rooms are downstairs.

living room Sonos is close to the main router.

tV room Sonos is close to a second hard wired router.

we only have 1 wi fi across the property and no issues there.

im finding it impossible to get both speakers to show in the app at the same time. I can get them to show up independently depending on where I am in the house. So, impossible to connect them as a group. I’ve factory reset both and no joy. I’ve also followed a chat call and no joy there.

no idea where I’m going wrong. Any suggestions would be much appreciated please?

thank you