ethernet W5500 shield will not work

I have a system that was running well. It has both UNO and Mega boards using the old style W5100 ethernet shield. In trying to switch one of them to the new shield boards with the W5500 chip nothing works. The new boards will assume the correct ethernet IP and can be pinged but that is all they will do. They will neither transmit or receive on either the UNO's ( some old and some brand new ) or Megas. The W5100 boards work perfectly anywhere we put them. The only changes we have tried to the software were to install an Ethernet2 library and try that. The W5500 boards will not work on either the old Ethernet library or the new version 2 library. We have some systems that use the Client form of communication and some that use the UDP system. Both were working fine with the W5500 and neither will work with the W5100. We have tried 3 of the W5500 shields purchased from Spark Fun and listed as genuine Arduino certified. They have made in Italy stamped on the back. Any ideas.

Never used these , but there are some google hits on these and various posts here :

Found this , dunno if it helps:
“The w5500 will exhibit erratic behavior without a hardware reset of the wiznet chipset before calling Ethernet.begin. I spun out for days on this; sometimes dhcp assigned an ip, most times Ethernet.begin just hung. My dhcp router table had spurious entries with crazy lease times, tried different routers; all unreliable. I put a LED on SS so I could see if they were talking… Then I manually tried a reset to gnd before calling Ethernet.begin and like magic negotiated with dhcp everytime. Moved reset to code and now this is solid as a rock.”

Thanks for the response. Pretty sure it does not apply to my case as I do not have a router on the networks and so no DHCP could be assigned. I am assigning static IP to these devices with the Arduino code. They take the assignment of the IP and I can ping them and they are there so I know they have a working IP address.