The seedlist of A is localhost. 
Seedlist of B is localhost, A_ipaddr and
seedlist of C is localhost,B_ipaddr,A_ipaddr.
 
Using localhost(or own IP address for non-seed nodes) is not a good practice.
Try
 The seedlist of A : A_ipaddr. 
Seedlist of B : A_ipaddr
seedlist of C : A_ipaddr