This article applies to:

ILHeader-10300-1 e-file error

This happens when the phone number is missing for the business representative.

IL Return Header (Rule ILHeader-10300-1): Either IL-Header BusinessRepresentative/Phone or IL-Header BusinessRepresentative/ForeignPhone is required

Select Organizer
, then States
.

Select Common State
, then General Information
.

Select Basic Return Information
.

Go to the Signature Information
tab.

Enter the phone number in
Column H
for Illinois
.

Do a full recompute, then recreate the e-file.