I had high numbers of MME Fails caused by wrong user profiles from Core side.
Also need to check with your Core team if user profiles are correctly configured.
For ERAB setup failure, you can put trace/packet mirror on s1ap of those eNb.
In trace, reason can be find out.
In MME, trace/ packet mirror need to register.
Bro, Please try to understand the Call flow of layer 3 messages that when the
MME sent message " S1 Initial Context Setup Request " to enodeB which contain default bearer "SRB1 QCI 9 request and enodeB sent (1) Security Mode Command & (2) RRC connection Reconfiguration message to UE. This failure occur mainly cause of weak RF coverage of UE or Connection lost but eNodeB unaware of it.
Optimization Action are :
Increase value of N310 and T310
Improve RF coverage.
You can check all the possibilities from radio side , check traces any particular cause for MME fails…I also see mme failures increased due to pci confusion… your mme fail count numbers are quite big…check any activities from the day of fails start…you will get it…