What is IRS code 5511?

If you mean Internal Revenue Code Section 5511, it has to do with the manufacture of fruit concentrates. You probably mean Electronic Filing Error Code 5511 which means that your direct deposit request was returned by the bank due to some error you made and therefore will be mailed to you after it is received back by the IRS. This will add at least two weeks to the process. Be glad that it was not deposited into someone else's bank account and them spending it due to your error.