i'm facing strange behavior in my lap which consists of p-cscf, i-cscf, s-cscsf, FHoSS for HSS

Registration is ok and ICSCF is performing well but when it comes to calls, INVITE Call between two ims users is not passing from scscf to icscf

the flow should be : P-->S-->I-->hss

i can see invite massage is going out scscf to icscf with all monitoring tools, but no incoming Invite massage to icscf not on sip level and nor on networking level (tcpdump)

Actually i don't know where the INVITE packets are going 

Any advice

Regards