Check whether your PC has the valid IP(not 169.254.xxx.xxx). If it has a valid IP, use it to ping 8.8.8.8. If it can ping normally, the problem is related to DNS. If not, use the PC to ping Router's...

I think you can connect two PCs to SG1016PE and GS108T. And use two PCs to ping each other to check the problem.

Firstly your router needs to support multiple DHCP servers then it can issue the IP addresses of different subnet. Then you can refer to the FAQ..... https://www.tp-link.com/en/faq-1630.html Maybe...

Try to set up speed&duplex on your PC. Set to 1000M.

That's strange. Maybe you can download the utility from TP-Link official website and find the switch again.

About the problem which GS108T cannot power on your POE devices, you can check their POE standard, whether they are compatible. About TL-SG1016PE doesn't show Tx data, you can connect two PCs to the...