makeWebRequest works in simulator, -300 response on Fenix 7X

The log file on the watch just has a -300 response, nothing else is provided to put in the log.

I tried resyncing the watch from the Connect IQ app on my Pixel 7, no luck.

I enabled WiFi on the watch and did a WiFi sync which worked, but after that still -300.

There's no connection attempts from the watch in the server log.

It's an actual registered domain name with a functioning DNS in the url, not an IP address. It's a Let's Encrypt certificate, not self signed, server is nginx and PHP-FPM.

The JSON response is 530ish bytes, so it shouldn't be a size issue.

No parameters (restful url), options are these:

            {:method => Communications.HTTP_REQUEST_METHOD_GET,
               :headers => {"Content-Type" => Communications.REQUEST_CONTENT_TYPE_URL_ENCODED},
               :responseType => Communications.HTTP_RESPONSE_CONTENT_TYPE_JSON},

What else can I look for or try? Again, it works in the simulator so I'm fairly certain it's not a code issue, but this is CIQ so I'm open to "try it this way instead" if that's what it takes.