if your student visa in your current passport then this can be reason.If not this cant be reason they dont see it on record.And if they see it and you are from Myanmar your passport also can be problem.Another problem is 1 month is very few must be 3 or more months in your bank account then this will be strong account.There is no other reason except these
category of this visa must be NON O.This is totally wrong.can give a name Non O longterm residence.Who can be a tourist and can have a tourist visa 5 years in a country
change passport always better.Seeing rejection stamp on current passport is not same not seeing any rejection stamp.Believe me.Also agencies are reccomending same.Change passport not cleaning everything(your history)but helping many things