Afr stuck/not working
 

So I am running into a small problem. A few day ago my (digital) afr gauge suddenly malfunctioned. It was only displaying 14.9 afr and somethimes changes to 15 or 14.8 but it is mostly stuck at 14.9. I use an app to read the afr gauge from my megasquirt so the afr gauge itself isn't the issue, I also bought and installed a brand new bosch Lsu 4.9 wideband o2 sensor which also did not fix the issue.

can anybody help me point out where I could look next to find the issue? Because I am a bit lost on what sensor's/ wires to check etc.

Thank you for your time!