@LoraW
What is the router model number and who is ISP (internet service provider)?
Also, when you checked that you are not blocking it, did you verify that MAC Filter was not enabled within the router? (how did you check you weren't blocking it via the app, exactly).
I think I would first start by restarting all my network equipment (modem, router, any peripherals like extenders and such) and then start looking at the router settings. At first glance, either a firewall or a filter setting should be investigated. I would then see if the Ultra works via ethernet as well.
Hard to believe you would get two bad devices, but I guess not out of the realm of possibility.
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