@ Merve,
You're right that we shouldn't be judgemental.
However, many teachers rightly understand that their student does, indeed, suffer from low self esteem & shyness.
If the teacher is emotionally intelligent, he/she will pick up on body language, even online, through eye contact, facial expressions etc. Even if the camera is turned off there's tone of voice and other such cues.
To answer this question we have to assume that the student lacks confidence.
So, I believe that it's easy to build confidence by relaxing & smiling, pacing the mood of the student and trying to get on their wavelength.
Then give them a task with a small degree of challenge but easily achievable. Put the student in the driver's seat. Praise his performance. If it's 99 percent substandard, praise the 1 percent that was excellent. Build trust from there, build bridges.
You'll not only help the student to learn, he'll gain self confidence to achieve more in every day life.