trumperl Let's make things clear:
1 You are using the AZ-GTi mount
2 Connect the AZ-GTi to the ASIAIR thru an EQDIR cable
3 The ASIAIR App shows the Serial Connected
4 But it cannot connect
So, we need to ensure:
1 If you switched the AZ-GTi to EQ mode with its SynScan Pro app?
2 How about change the Baud to 115200?