@Joshua ******
did you get an email from them or just the automated update from the e-system? If just the automated update, you should also be receiving an email (maybe tomorrow) and it might say the reason why. They are usually up front on why an application is canceled, it is when it is rejected that they often don’t tell you. Cancelations, can be due to applying to an embassy that you are not allowed to apply via or also very common, spelling error in the passport information that you supplied. Also adding a middle name that one has but isn’t on their passport, or if you got your passport issued while overseas, listing the embassy or that city/country as where it was issued, can all lead to cancelations.