Gigabit

The gateway address is wrong, or at least, wrong for this network. The subnet mask defines the network portion to be the first 8+8+4+0 = 20 bits from the left. The network part of the PLC address is hence 172.16.0, but the network part of the gateway is 172.16.240, that is, different networks. If you don't need the gateway, leave it out. If you do, the PLC has to be in the same network as it. I'm not confirming this is the cause of your problems, however you have seemed to indicate the gateway address is invalid for this PLC addresses, and you are correct.

SPIDER 5TX is just a simple (although industrial) unmanaged switch. It does feature auto-negotiation, so if anything connected to it does not have auto-negotiation turned on, there will be be a duplex mismatch and perhaps rate as well. Once this is sorted, I'd try to get short connections proven (divide and conquer) rather than the full end to end connection. Does it work if you plug in directly to where you have the SPIDER connected?

The COM Redirector utility has a quirk in that it does not like leading zeros in the IP address. For example, 192.168.2.010 should be 192.168.2.10 This is documented in one Rockwell knowledgebase article, but not, unfortunately, the one titled 'Troubleshooting the 1761-NET-ENI'.