Ideally you need a known good working node to check your gateway, is there anything you borrow? If your gateway then picks up the that node, you can concentrate on your node, if it doesn’t, then you know to work on the gateway.
The RSSI of -116 would imply that your MSP430 + RA-02 radio is either a fair distance away or in a metal box or has no antenna - so it may be that your node isn’t transmitting successfully but you are picking up another nodes signal that is some distance away.
Is there any debug output from your node to confirm the LoRa module is happy? Is it set for OTAA or ABP? Can you change the spreading factor to improve the signal?
The GitHub code you reference is for a SX1276 (868MHz) but you will be using a SX1278 - you may need to look at the spec sheets for both to see what changes may be required.