with and without quotes (because of the spaces in the filename (which I can’t rename as the usb drive is hard-wire named that)) and that gave a different error, but all I need is “sync all folders now”
Using curl in a terminal window, you can easily check if the REST API works. Let’s assume Syncthing runs on a machine called studio1 in the local network. Type the following command, substituting server name and API key with your own:
curl -X GET -H "X-API-Key: Ziegheizee7do7Je8uiMiepu8Abeevee" http://studio1:8384/rest/system/version
You should get a JSON response like …
… but I didn’t get the proper response, instead got
Double check the api key. Maybe there’s a simple copy&paste error, maybe you are copying from the wrong config.xml file (you can copy from the web UI to be sure that’s not the case).