I have been having the same issue with my router of the same model. I have tried myriad other steps to try and fix the problems I am having with little luck. I have attached my connection data, can you take a look and see if anything looks out of the ordinary or if you have any recommendations? Thanks in advance.
Sorry for the delay in responding...
Since last week, I hardwired a few of my devices with ethernet via powerline, and I don't seem to be having problems anymore with those devices...it's just the wifi connection. Devices will indicate that they are connected, but no data is getting through, and other devices can't see them on the network. It's like they are being blocked off from the rest of the network. A reset of the modem or respective devices temporarily fixes the issue, but the problem comes back after an amount of time.
I have tried tinkering with the channel (I am in a very busy/dense area for wifi-signals, and by scanning with my mac I found that channel 6 had less interference than 11, so I changed the channel on my router to 6). Although, a scan of networks in the area revealed that my neighbor is using channel 2 on a 40mHz bandwidth...I wonder if this is causing problems. I wouldn't think it would be causing problems when my router was on channel 11. Anyways... I moved the router to the other side of the room to rule out interference with other devices/walls, etc. I tried changing the security settings to WPA-PSK instead of WPA2-PSK, as recommended in other forums, and this did nothing to help the problem, so I switched it back. AP Isolate is off, and UPnP and Multicast are enabled...I'm hoping someone else has an idea of what might be happening.
I atttached a screenshot of my signal over a 30 minute period. The green line is my 2.4GHz network and the pink is the 5GHz network. I wasn't really doing anything to use my internet or network during this period of time, and I notice that the 2.4GHz network dropped out a couple of times...not sure what could be causing this or if it's normal. Let me know if you have any thoughts or suggestions. Thank you in advance!