Hi! I was wondering if you found a solution ? I got the same arduino and like you it seems impossible to connect to the sigfox servers using the basic configuration sketch. I live a few kilometres south of Brussels, in Belgium and according to the coverage maps on sigfox’s website it really should not be a problem...
I did notice on my board that the orange led sometimes actually blinks when trying to send the message but often will slowly dim in and out in a very irregular fashion rather than blink.
Could the antenna be the problem? I read on other forums that some people opened the antenna to re-solder the connectors... I am a bit reluctant doing so as the antenna is brand new but I’d really like this to work.
Having read the docs and example code over and over before buying my mkr Fox, having checked coverage, I really thought this first “hello world” part would just work, easy as pie...