A professor, in my culture, is always called Dr. so and so. Not even called Prof. so and so. Certainly it's a taboo to call my professor by their bare name.

For a while I was an instructor, and I begged the students to call me by my first name, they NEVER DID. I was teaching at a continuous learning organization, so my students were, in many cases, much older than myself, but this gesture is considered respect.

Easy Professor Doctor Peaceful Muslima..:))

Salam