opened xterm from
/usr/share/applications
and ran the command
DISPLAY=:0 gnome-terminal -x sleep 10
Just after this a Terminal appeared.
I have closed the both xterm and Terminal I tried to open Terminal again and it worked perfectly! Thank you very much for the answer
Recently I upgraded Python and I think that caused the issue. I upgraded it to Python 3.6 (here in the shebang line you should mention 3.5)
I have modified the below file:
sudo vim /usr/bin/gnome-terminal
Modify the first line from #!/usr/bin/python to #!/usr/bin/python3.5