Unable to connect to remote machine

edit

I have a remote Bitnami virtual machine that has ROS Noetic installed on it. I can connect to the vm using a .pem keyfile. I am trying to export the ROS_MASTER_URI running on the server to my computer and remotely connect to it.

I have created a ROS environment shell script named env_remote1.sh with file path /opt/ros/melodic/env_remote1.sh With the following code:

#!/bin/bash

export ROS_MASTER_URI=http://remote1:11311

source /opt/ros/noetic/setup.bash
source /home/remote_user1/catkin_ws/devel/setup.bash


exec "$@"

And have the following launch file, named remote.launch on my local system to connect to the vm:

<launch>
    <machine
            name="<vm name>"
            address="<ip address>"
            env-loader="/opt/ros/noetic/env_remote1.sh"
            default="true"
            user="<username>"
    />
    <node machine="remote1" pkg="beginner_tutorials" name="hello_doubles" type="hello_doubles" />
</launch>

When I try to launch the file, I get the following error:

remote[<ip address>-0]: failed to launch on <vm name>:

Unable to establish ssh connection to [bitnami@<ip address>]: Server u'<ip address>' not found in known_hosts

Looking at the answers https://answers.ros.org/question/4144... it seems that I will have to generate the public-private key pairs again with a different algorithm. However is there a way to resolve this issue with the currently existing key?