High ERAB drop and low RRC CSSR

I’m new in the industry. I need your support, please. I’m facing issues with the Nokia LTE L07 frequency one sector having high ERAB drop and RRC connection setup Success rate is decreased… On what should I base myself to effectively carry out the root cause analysis such that it should meet the threshold?

check first counters issue

drop counter :check reason of drop (RNL ,double S1,S1 outage, HO ,MME )

RRC counter :check reason of RRC failure (RRCcompl_missing ; RRCcomp_error,RRCcomp_Est_fail_RRMRac)

Thanks brother