While executing the following circuit (consisting 16 qubit and 4 classical bits) I am getting "Error in transpilation process. [1003]" error. I have a group of 2 operations (you can observe circuit duplication in the figure). Is it a valid circuit? If not why it is not?. Why am I getting error? (My target backend is ibmq_16_melbourne).
OPENQASM 2.0;
include "qelib1.inc";
qreg q[8];
qreg qGrp1[8];
creg c[2];
creg cGrp1[2];
h q[2];
h q[4];
h q[6];
x q[7];
x qGrp1[1];
h qGrp1[2];
h qGrp1[4];
h qGrp1[6];
x qGrp1[7];
cx q[2],q[3];
cx q[4],q[5];
cx q[6],q[7];
cx qGrp1[2],qGrp1[3];
cx qGrp1[4],qGrp1[5];
cx qGrp1[6],qGrp1[7];
ccx q[6],q[0],q[4];
ccx qGrp1[6],qGrp1[0],qGrp1[4];
ccx q[7],q[1],q[5];
ccx qGrp1[7],qGrp1[1],qGrp1[5];
x q[6];
x q[7];
x qGrp1[6];
x qGrp1[7];
ccx q[6],q[0],q[2];
ccx qGrp1[6],qGrp1[0],qGrp1[2];
ccx q[7],q[1],q[3];
ccx qGrp1[7],qGrp1[1],qGrp1[3];
cx q[2],q[3];
cx q[4],q[5];
cx qGrp1[2],qGrp1[3];
cx qGrp1[4],qGrp1[5];
measure q[3] -> c[0];
measure q[5] -> c[1];
measure qGrp1[3] -> cGrp1[0];
measure qGrp1[5] -> cGrp1[1];