Queue Source not being processed by DPSK Demod Block

Im having an issue with the my dpsk demodulator block not processing
any data provided by a message source block.
This is how I’m passing it to the queue:

msg = gr.message_from_string(processed.tostring(), gr.sizeof_gr_complex)
tb.source_queue.insert_tail(msg)

The “processed” data is a numpy array. Is there is an issue with this
data type?

-Travis