Insufficient bandwidth for streaming with Fiber
I have 100 mbps Fiber and upgraded about 1 month ago (modem remained the same). Previously, I had no issues with streaming with 50mbps and no fiber.
I've been receiving "insufficient bandwidth" notifications on Amazon Prime 4K streaming. Additionally, my cell phone's wifi is effectively useless when I am streaming something on the TV. This was not an issue before I upgraded service. AT&T speed tests show normal upload and download.
I have very few connected devices. Xbox (via hardwire) and my phone.
I've reset/restarted the router and Xbox several times, with no success. I've also changed the ethernet cable with no success.