hello everyone,please help,my visa has been cancelled today in Vietnam without reason,what should i do?

update,i took photo of every step,and i just check again,it's exactly the same as what I filled in my passport.

The only reason I can think of is that I did not write China as the place of issue, but the information I filled in is the same as in my passport, which is the province where I was born.and my friend also filled in the province, her application was approved in Jakarta.

The embassy was closed for the holiday. It was really frustrating that there was no specific reason for the cancellation in the email. I guess I will have to go to the embassy next Monday to ask for the reason.