I have been using this for 1 1/2 years with no issue. Was watching content in 4K when it buffered for minutes. I realized I had inadvertently disconnected the ethernet, it had been using Wi-Fi, reconnected. Now it won't play prime content in 4K. It plays Netflix and YouTube content in 4K, but not prime content. Checked my settings, all correct there. Rebooted several times. My internet speed is easily fast enough to support this. No 4K prime.