LoPy4 hangs on receive loop while in c-clas

[Jamie]

while True:
    try:
        rx = s.recv(64)
        if rx:
            rxStr = str(rx).split("'")
            s.send("Sw#," + rxStr[1])
            index = int(rxStr[1])
            i2c.writeto(56, 255-index)
            print("swSet = ", index)
            wdt.feed()
    except Exception as error:
        print(error)
        s.send(str(error))
    time.sleep_ms(500)

Greetings,
I'm hoping someone might see a problem in this receive loop. The device is in c class mode when it reaches this code and then it waits to receives data that is sent every minute. The data is a incrementing number and the number is echoed back thru the gateway and into a database for testing. The problem is that the devices will work fine for awhile and then hang until the WDT resets. I have five devices working side by side with the message coming in to each device spaced one second apart and they will all hang but how offend differs between devices. I also miss messages but that does not concern me as much as the 5 to 7 minutes it takes to restart the device. The i2c chip is a I expander running switches. Do I need to do something as simple as adding a time.sleep() somewhere?
Thanks

[Jamie]

while True:
    rx = s.recv(64)
    time.sleep_ms(10)
    if rx:
        time.sleep_ms(10)
        rxStr = str(rx).split("'")
        index = int(rxStr[1])
        
        try:
            i2c.writeto(56, 255-index)
        except Exception as error:
            print("i2c",error)
            
        startTime = time.ticks_ms()
        s.setblocking(True)
        time.sleep_ms(10)
        
            try:
                s.send("ack")
            except Exception as error:
                print("send ",error)
                
        time.sleep_ms(10)
        s.setblocking(False)
        print(time.ticks_ms()-startTime)
        wdt.feed()

@jcaron thanks for your response. The problem is in the s.send(). I added the setblocking() statements around the statement along with putting it in its own try/except but they are still resetting at least 12-16 times a day. Is there any thing else you think I should check? Gateway setting? I'm using a Multitech Conduit gateway that's running node-red.

Thanks again

[jcaron]

@Jamie you should probably add a few logs in order to determine exactly where it hangs (receiving or sending over LoRa, sending over I2C).

Is the socket set to blocking or non-blocking?