Hi @gauteh,
It might be helpful if you looked over the steps in this guide: Help! My Notecard is not connecting to the Cell Network!. Specifically, I’d like to see the results of a card.wireless call.
Also, which Notecard model and which antenna are you using? This seems like it could be a signal/connectivity issue that can manifest during TLS authentication since you’re sending a relatively large amount of data (~4KB) at the time.
Rob