Any reason to contention resolution always fail after msg3?

Hi Experts,
An issue in NSA with RACH.
Is there any reason contention resolution always fail after msg3?

What vendor?

It is Open RAN, not legacy vendor.

Does the UE get msg4?

gNb sent but UE never decode it.
Do you now maybe, is it possible to use cont-free in NSA for initial access?
For testing just.

Yes, it should be possible to use contention free RA for ENDC deployment.

Did DCI decoding happen for msg4 with tc-rnti?

Don’t see it in msgs.
After msg 3 only cont-based failure.

Do you see something like this on UE side?

There could be strong interference in DL that stops UE to receive/decode msg4 and it’s C-RNTI
What’s your pathloss or SSB RSRP?

NR cell radius?

It is similar but SINR is good.

The UE considers the contention resolution unsuccessful

  • If MAC contention resolution timer expires.

You can increased Maximum number of preamble transmission