New publisher discovered on topic, offering incompatible QoS.

edit

I am trying to run a program to control a roomba with ROS using the messages from the IRobot repository (https://github.com/iRobotEducation/ir...). I am trying to get the wheel speed using the 'wheel_vels' topic, but am struggling to do this. My code looks like as such:

//within node definition class

self.subscription = self.create_subscription(WheelVels,'wheel_vels' ,self.get_speed, 1)

self.current_speed= None

def get_speed(self,msg):

self.current_speed = msg.velocity_left

However, when I try to get speed, I get the following error: "New publisher discovered on topic 'wheel_vels', offering incompatible Qos. No messages will be received from it. Last incompatible policy: RELIABILITY"

How can I get past this error? I'm confused on what's causing it and how to fix it.