XBee PRO S3Bs intermittently communicating and unusual behavior

I am running an application on XBEE PRO S3B.
I cant seem to transmit messages among the two modules. They rarely and intermittently transmit.
I configured then through XCTU-NG and communicated among them in serial console. But they don’t communicate through the application.

Also the code startup takes about a minute and the app banner displays hardware address, version and firmware as all 0s.

Is it possible to completely erase the app as well if that becomes necessary?

Would really appreciate help on this!!