Nodemcu Busy while Power On issue.

I am having nodemcu unit . I have connected TX2_nodemcu to Rx_out of MODBUS device and

RX2_nodemcu to Tx_out of MODBUS device. I could able to get read and transmit data successfully. The

problem i am facing when power went off.when my power went off TX and RX line kept connected to

modbus unit. Where nodmcu wont reply for any reply itself. Now if remove tx and rx line from nodemcu,

after pressing reset button, nodemcu start working. If i connect tx & rx line in this situation code work

properly.How can i avoid this? i wanted to nodemcu shpuld goto online when power off & power on

without touching RX and tx line.kindly guide some suggestion for above error