When I had my A8, it was running on wifi – so that should not be a problem. The problem is your new router/the settings. Hard to say anything, when one does not know the brand, the settings, the strenghts of the signal.
After resetting it, I would try connecting it with a cable – that some times helps and can give you access to the menu for the wifi password. Use the Bang & Olufsen app to set it up.
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