I checked the state Schema for e-filing requirements and was able to confirm that this field, the New Mexico Business ID#, is not required for e-filing. In other words, you can e-file your return by leaving it blank, try giving that a shot. Also, the character limit is set by the state DOR, and cannot be altered by ProSeries, thus it must remain at the seven-character limit. Perhaps try contacting the state DOR and confirming the cause as we have not seen an e-file reject for this issue in either TY20 or TY21. Hope that helps.