iOS App Code Issue Fix & Upload Tutoring

I'm having trouble with my iOS app's backend logic, preventing me from uploading it to the App Store. I need an expert who can not only fix these code errors but also teach me how to rectify such issues in the future. Ultimately, I would like to learn the process of uploading to the App Store.

Key requirements:
- Expertise in iOS app development
- Proficient in identifying and fixing code errors, particularly in backend logic
- Experience with App Store submission process
- Ability to explain complex technical issues in a simple, understandable manner
- Patient and effective teacher