Hi, I have configured kamailio as Ims server with pcscf,icscf,scsf and hss in 4 different vms . After that I use zoiper client for testing the call flow . Registration is successful .It goes via UE -> Pcscf -> icscf -> scscf and returns back with 200 OK . Registration is happening with authentication from hss . When I make an INVITE , it goes from UE -> PCSCF -> SCSCF -> ICSCF -> SCSF and s-cscf gives *403 - Domain not served *to icscf and i-cscf returns to p-cscf with the same error . I am not seeing any errors in scscf and i-cscf . In pcscf , I am seeing an error like *Error : <core> [core/lvalue.c] :lval_pvar_assign() : setting pvar failed * *Error : <core> [core/lvalue.c] :* *lval_assign():assignment failed at pos* *I have configured alias in all cfg files and configured DNS server* In pcscf.cfg file -> pcscf.sip.example.com In scscf.cfg file -> scscf.sip.example.com In icscf.cfg file -> icscf.sip.example.com And for hss -> hss.sip.example.com What should I do? Kindly advise. I am struggling with this issue for a week.kindly do the needful. Version - kamailio - 5.3.3 I need a normal call flow to be established between two clients.kindly help . On Wed, Apr 8, 2020, 1:01 AM David Villasmil &lt;david.villasmil.work(a)gmail.com&gt; wrote: