gnuradio flow graph starts and stops

Hi,

Please help with the following issue. Thanks in advance

OS: Windows 11

Gnuradio version: 3.8.3.0 

(Python 3.8.0)

Source: radioconda 2021.04.08

Observation: FLow graph starts, output windows appear and stops in a fraction of second.

Error: 

gr::pagesize: no info; setting pagesize = 4096
Traceback (most recent call last):
  File "D:\\Google Drive\\Zafar\\SDR_Course_WirelessPi\\Codes\time_shift_effect.py", line 284, in <module>
    main()
  File "D:\\Google Drive\\Zafar\\SDR_Course_WirelessPi\\Codes\time_shift_effect.py", line 269, in main
    signal.signal(signal.SIGINT, sig_handler)
AttributeError: module 'signal' has no attribute 'SIGINT'

Regards

Zafar