Looks like you haven’t assigned a configuration to the windows machine
Here is the step-by-step guide for sidecar which includes how to assign the configuration.
More specifically it looks like this below… though in this case they are assigning a filebeat config to a linux machine. Once you assign it in the Graylog GUI, Graylog will push the configuration to the Windows machine and the service will restart.
On a side note, Elasticsearch is supposed to stay at 7.10 for now ( you are at 7.11.2) You may want to pin it at that version so it doesn’t’ get too far away from you/guidelines.