MavProxy not connecting after installing Gazebo plugin

I was following the SITL instructions on the main docs site (Setting up SITL on Linux — Dev documentation); i am on Ubuntu 20.04. I got the SITL with MavProxy working just like in the instructions; the command sim_vehicle.py --console --map launching everything as the last step.

I then moved on to get it to work with Gazebo following Using Gazebo Simulator with SITL — Dev documentation, I installed Gazebo9, the dev dependencies, the khancyr gazebo plugin.

Launching Gazebo with gazebo --verbose worlds/iris_arducopter_runway.world and then the SITL with

cd ~/ardupilot/ArduPlane
…/Tools/autotest/sim_vehicle.py -f gazebo-zephyr --console --map

I get an error

SIM_VEHICLE: Run MavProxy
SIM_VEHICLE: “mavproxy.py” “–map” “–console” “–out” “127.0.0.1:14550” “–out” “127.0.0.1:14551” “–master” “tcp:127.0.0.1:5760” “–sitl” “127.0.0.1:5501”
RiTW: Starting ArduPlane : /home/hermamr1/ardupilot/build/sitl/bin/arduplane -S --model gazebo-zephyr --speedup 1 --slave 0 --defaults /home/hermamr1/ardupilot/Tools/autotest/default_params/gazebo-zephyr.parm -I0
Connect tcp:127.0.0.1:5760 source_system=255
[Errno 111] Connection refused sleeping
[Errno 111] Connection refused sleeping
[Errno 111] Connection refused sleeping
[Errno 111] Connection refused sleeping
Failed to connect to tcp:127.0.0.1:5760 : [Errno 111] Connection refused
SIM_VEHICLE: Killing tasks

It seems that MavProxy isn’t connecting with the SITL anymore? But I am not sure why that would be. And now when I try to run without Gazebo using the steps at the top of my post I get the same error; so it seems not related to Gazebo, but happened after trying to use Gazebo for the first time?

Why would I get this error, I am really new to ArduPilot and ArduPlane so maybe it’s something real obvious I am missing but stepping through everything I did I can’t figure it out.