I have received a reject, Error 903, on an attempted e-file of an AZ Form 141 Amendment.  The explanation says, "Error 903: EIN/SSN has already been used in another tax return; SUB - ID has already been used with a return for the same tax year."

The EIN has to be the same as on the originally filed return.  I do not know what the term SUB-ID means.

Any insights will be appreciated.