@Kevin_Z Hi! i have a similar problem, today i received a TL-SG116 because my old Tenda 8-port gigabit switch suddenly stopped working (i had 1 cable to the router, 1 cable to a 2 level daisy chain configuration with several devices, and 5 more devices directly connected to the switch) i tought the switch could not drive the 23 devices i have so i decided buy this one from tp-link. When i connected the new switch i noticed that suddenly stop the internet connection but the devices still retain ip address and they actually appear in the configuration page from my router, restart the switch, again i have internet and then 3 minutes later the same drop, this happened several times until i realize that when i connect anything to port 4 the switch stop the traffic, is this a factory problem? i still can return the switch. The weird thing is that suddenly the switch start to work normally and several hours past without problem and with every cable connected, even port 4 one, what can i do to be sure it was a firmware update or something on the router and discard the switch from the problem?

@mjs 

I have a very similar problem: last week I received my new modem, the Proximus b-box3. My switch TL-SG116E worked perfectly on the Proximus b-box2, but when connected to the b-box3 I lost the internet connection. I have other switches which work perfectly fine when connected to the b-box3, but the TL-SG116E makes I loose my entire internet connection. I have tried using different ports on the b-box3 and on the TL-SG116E to interconnect both, but the problem persists.