Hi @Willem -
Can you share what version of BlueOS you’re using? This is on a BlueBoat?
After setting serial port configuration, do you save and restart the autopilot via the button at the bottom of the page?
What is the IP address of the Septentrio GPS, and how is it connected to the system? Via ethernet switch?
It may be worth trying the NMEA injector instead of the autopilot serial 2 approach…