LAN not working on Ethernet Shield 2

Beginner here to Arduino and first post to this forum. Purchased Arduino Ethernet Shield 2 for my Arduino Uno. Successfully installed Ethernet2 Lib.

I then tired most of the Example Sketches for the Ethernet2 Lib and could not get any to work. I had another PC open, connected to my router (DHCP IPs page) and it never assigned. Same error every time...can't connect to DHCP...

Read up on many posts regarding this topic (Beginners guide to Arduino Ethernet Shield 2 - Networking, Protocols, and Devices - Arduino Forum) but it seems like few have this issue.

I should also say that I finally got a program working logging DHT22 sensor data with the micro SD card for the Ethernet Shield I know that part of the unit is working...

Assigned IP if DCHP unsuccessful: (router allows 0.50 to 0.100)
(I could ping this OK after uploading)
Class C subnet
MAC address from sticker on back

Lastly, when RJ-45 cable is connected, all 4 lights in the back light up (with the "ACT" occasionally blinking) and both RJ-45 lights on solid but not blinking...

Appreciate any support or sample scripts to run besides the ones included to troubleshoot....thanks!

Have you tried using DHCP without a SD card in the shield's slot? If you don't remove or disable it before the dhcp request, the dhcp service will fail.

Yes, I did all that DHCP troubleshooting without an SD card inserted.


lots of warning also in this library (Ethernet2) when you set up preferences at max compiler warnnigs.

Is it linked ?

for exemple :

C:\Program Files (x86)\Arduino\libraries\Ethernet2\src\Dns.cpp:285:58: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]

C:\Program Files (x86)\Arduino\libraries\Ethernet2\src\utility\socket.cpp:328:11: warning: variable 'status' set but not used [-Wunused-but-set-variable]

Update: Was able to get it work by setting digital pin 10 as a high output! However, when I load up simple HTTP sketches (turn on/off LED, get A0 value from LDR, etc)...the web page automatically refreshes maybe 3-6 times before losing connection. Tried several different example sketches with the same result. Also tried two different browsers (Chrome & Edge). Thoughts??