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I received a rejection as follows:  "The PIN for the first taxpayer on your return is missing.  The IRS e-file database indicates that an PIN is required.  You should have received a CP01A...  "  I have the letter with the 6 digit PIN but Turbotax won't let me enter it in the box.  It says, "Invalid, too many digits."  Why won't it let me enter 6 digits?