What could be reason for SRVCC execution failure?

Hello Experts.
What could be reason for SRVCC execution failure in New on air?
All execution are are failed.
What need to be checked?
Vendor Huawei.

Please check if NBRs are defined to 3G.
Also check 4G and 3G threshold like B2 and 3G RCSP threshold. Compare these value with your UE RF level quality or not.

Every attempt are failure.

Check all SRVCC related switch are ON and you can also compare parameter with existing sites.

Check trigger mode threshold like RSCP or ECNO or both.
Is this value aggressive set and also 3G has alarm, vswr congestion issues, no reply.
Apart from basic neighbor defined.

Fo VoLTE A2 is - 86.
B2 RSCP - 100 from intrarat hocomgroup.

Is it b1 or b2 based?

Hi, it is b2.

Trigger mode of SRVCC?
And trigger mode is RSCP?
B2 t1 and b2 t2.
And a1 and a2both.
As well as its trigger mode.
Check in interrat.
Intrarat is for intra and inter freq.

check priority for qci1 and qci5


B1 is - 110
B2 is - 43

Sometimes it happens due to ext interference or HW issue on 3G side, please make sure.