W5500 Stops Communicating with Server until Switch is rebooted

Hi All,

We manufacture a module that uses the W5500 and it is used to send small packets of data (30 bytes or so) using TCP/IP or UDP to a remote server. We have used the W5500 for the last 3 years without any issues. We have a customer that uses our module and from time to time for no reason the server stops receiving the messages from one or more of the modules, the customer has 100+ modules installed. You can ping the module and it responds fine, the firmware in the module will also perform a full reset and initialize on the W5500 if it fails to deliver the packet of data after x number of attempts.

The only way that communication can be re-established is to power down the switch that the module is connected to. The customer uses a wide variety of switches (Netgear, TP-Link etc). What would make the switch block/blacklist the W5500?