The app uses information from the built-in Apple compass, so if the qibla is wrong then it’s most likely coming from the phone or watch itself.

Please open the Apple compass on your phone or watch and check if it shows true North. If not, you can recalibrate the compass by:

• Walk around your home or building a bit to help it recalibrate
• You may need to go down to the ground/main floor of your building for it to be fixed 

You can also try some of the calibration steps in this article: How to Calibrate iPhone Compass for Better Accuracy