They are afraid of losing face in generally.Not only teachers but also the people on earth.it's hard for man to face wrong or admit mistakes

Most teachers do not admit that they are wrong because they are proud of what they teach, and if they admit that they have made a mistake (they fear) it will hurt their reputation as a teacher. I too have made mistakes, but my students know that they have a fair teacher who is willing to correct herself - even in front of her students. I hope this helps you...

Can you give us an example? As a teacher, I'm happy to say to my students, "Hey guys, I made a mistake when i said that...........". In other cultures, teachers will not admit that they are wrong because they will lose face.

Because I am never wrong!

A comment about the wording of your question.... "Why do most teachers not accept that they are wrong?"............................ Not only teachers, but many people feel embarassed if they are wrong. But "to err is human".... that means that humans cannot always be right/correct. It is best to admit that you are wrong when you are wrong, and then do not make that mistake again.