All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ʻalayhi wa sallam, is His slave and Messenger.
There is no doubt that a video chat between a female student and young male teacher is a great source of fitnah (temptation); in fact, a mere conversation without seeing one another is itself a source of fitnah. Therefore, scholars emphasized the prohibition of having undue conversations with young non-mahram (marriageable) women. The Hanafi scholar Al-Khaadimi wrote, “It is impermissible for the Muslim man to have a conversation with a young non-mahram woman for no need because it may incur fitnah...” [Bareeqah Mahmoodiyyah]
The Hanbali book Kashshaaf Al-Qinaa' reads, “When a man greets a young Muslim woman, she should not greet him back so as to ward off potential fitnah.”
Hence, Muslims are enjoined to avoid this and to stay away from sources of fitnah and doubtful situations. Normally, people make such video chats in privacy; Satan may lure the person into sin and immorality, and he may surrender to his sinful desires and temptations. Indeed, it is better to be safe than sorry.
Allaah knows best.