Correcting send() for tagged stream block

Hi all,
I am trying to make 2 TX 1Rx tagged stream block(OOT). For 1Tx 1Rx, it
is working fine. I am trying to extend it. Now the problem is, I am not
being able to configure the send() function. With this code, one
transmitter transmits, but other does not work. The subdev specification
and frequency and other parameters are allocated correctly. I checked.
If I try make test, it does not show any problem. I checked the every
port of my USRP X310, it is working fine.

Here’s the code. I putting a short part where I have problem. Please
check and let me know how to correct.

// Data to USRP
num_tx_samps = d_tx_stream->send(d_in_send1, total_num_samps,
d_metadata_tx, total_num_samps/(float)d_samp_rate+d_timeout_tx);
num_tx_samps = d_tx_stream->send(d_in_send0, total_num_samps,
d_metadata_tx, total_num_samps/(float)d_samp_rate+d_timeout_tx);
usrp_echotimer_cc_impl::work (int noutput_items,
gr_vector_int &ninput_items,
gr_vector_const_void_star &input_items,
gr_vector_void_star &output_items)
gr_complex *in0 = (gr_complex *) input_items[0];
gr_complex *in1 = (gr_complex *) input_items[1];
gr_complex *out = (gr_complex *) output_items[0];
// Set output items on packet length
noutput_items = ninput_items[0]=ninput_items[1];
// Resize output buffer
// Send thread
d_in_send0 = in0;
d_in_send1 = in1;
d_noutput_items_send = noutput_items;
d_thread_send =
gr::thread::thread(boost::bind(&usrp_echotimer_cc_impl::send, this));
// Receive thread
d_out_recv = &d_out_buffer[0];
d_noutput_items_recv = noutput_items;
d_thread_recv =
gr::thread::thread(boost::bind(&usrp_echotimer_cc_impl::receive, this));

My system config is X310, daughterboard SBX-120 and I am using UHD-3.9
I checked the subdev specification, gain and frequency assignment. Those
are fine.
Please let me know how to correct and thanks in advance.

best regards