if it wasn’t a clerical issue and they wanted to deny you, it would have been a rejection, not a cancelation. You had to have made a mistake or the app’s photo reader entered something incorrectly. Did you leave the middle name box empty? If not, others have said it should be and specifically Chinese applicants have been canceled for entering their second first name in the middle name box.
The issues that popped up previously. For place of passport issued, did you state the country you are from, or did you list something else like province or embassy (if you received a new passport while abroad)? Correctly placing names in first and middle name slots. If you have two first names, placing both in the first name slot. Being in the correct geographic location. The scan of your passport page populates incorrect data into the cells, replacing I with l (one is I and one is L).
- one reason some are canceled is if you applied to the wrong consulate. Since Vietnam has the embassy in Hanoi and a consulate in HCMC, this has been an issue for some there. Also, do you have two first names? If so, did you list them both under the first name in the application or did you move one to the middle name slot?