Sigfox Callback failing to send to pybytes

[plsecker]

I have thus far failed to get a Lopy4/SiPy to successfully send to Pybytes. I have the green lights on the Provisioning page but the key issue appears to be the POST message. The Sigfox back end is showing:

[ERROR] - Base station 5743 - 2 seconds

600 - Unresolved network address - #4

POST https://sigfoxbridge.pybytes.pycom.io/sigfox/callback HTTP/1.0
content-length : 51
accept-encoding : gzip,deflate
accept-language : fr
host : sigfoxbridge.pybytes.pycom.io
accept-charset : UTF-8;q=0.9,*;q=0.7
user-agent : SIGFOX
content-type : application/json

{ "sigfoxId": "4D6157", "payload": "210404a00506" }```

[plsecker]

@plsecker Can someone just post the Callback url they have for a Sigfox device?
Mine (above) has been provisioned as:
https://sigfoxbridge.pybytes.pycom.io/sigfox/callback
(its listed under Devicetypes|Callbacks).

Bit bemused as to the lack of help on this. No response from Pycom either.