@jared. I retried the sketch as it is posted above, but with my VariableID and token and it works for me. Response looks like this.
Connecting to...
https://things.ubidots.com/api/v1.6/variables/56e816577625420c7db596/values?page_size=1&token=h5g5rSjUeYksa3GFQxiEbI8mrmu3
https_send_request_rsp_cb()
{"url": "http://things.ubidots.com/api/v1.6/values/56e8186f7625421a696d9d", "value": 20.0, "timestamp": 1458051183956, "context": {}, "created_at": "2016-03-15T14:13:03.956"}òòòò
20.0
https_unset_channel_rsp_cb()
I went to the endpoint you posted above and it looks valid. Last updated 03/09/2016 with the value 25.
Would you post the code you are using so I can have a look at it?
Edit: In the “_https.cpp” tab you created double check that your carrier’s APN settings are correct and that the appropriate code section is commented in. If your carrier uses APNs and proxies comment in that section(lines 18-21) and update the details there. Then comment out the section above. Lines 11-14.