That's because the IRS only accepts efiled tax returns for the current Tax Year. (efile.com)
In the year of bankruptcy there are two tax returns filed (a pre and post bankruptcy return), and since CRA's systems are not set up for efiling of bankruptcy tax returns at least one of those returns must be mailed to CRA, but for the years after bankruptcy e-filing is available, because they are returns for a full calendar year. (bankruptcy-canada.com)
Using eFile allows you to file federal and state forms at the same time or separately. (ncdor.gov)