App says internet:offline

I’ve seen a similar issue here. But what worked for them didn’t work for me. 1st I have AT&T U-verse. I have a RAX12 wired to one of the gateway ports. And I have a EX8000 extender upstairs. When I 1st set it up a couple of months ago, everything seemed to work great. About a month ago, I noticed some slowing down and drop offs. Right now, app says offline on router and extender. Equipment connects. But internet limited. Fire stick connects but shows connected with problems. My ESPN app doesn’t load anything. Google loads but no pictures. Some videos won’t play. I’ve tried rebooting, resetting, and relocating. Firmware updated to most recent .114. Nothing’s helped. What am I missing?