I have gotten the same error every time I use roslaunch for all of the quizzes on ROS in 5 days with Python. My launch files are correct. I was wondering what else I could possibly try fixing?
RLException: Unable to launch [service_move_bb8_in_square_custom_server-1].
If it is a script, you may be missing a ‘#!’ declaration at the top.
The traceback for the exception was written to the log file
This is a simple problem (I guess). You must include the interpreter identification line with shebang (#!) in python scripts. Just include this line on the very top of your python programs:
#! /usr/bin/env python
import rospy
# Other imports
# Program Code
# End of Code
Do not forget to do chmod 755 <python_file_name>.py so that the file becomes executable!
Let me know if your problem is resolved after doing these steps.