The error code itgenrst007 signals that a required field has no data.
The custom report has been reviewed and modernized, but no relevant cause was found. It is recommended to provide delegation as described on Access via delegation on Invantive Cloud for consultants. The problem occurs only on one legal entity and very probably some data is corrupt or incorrect, like a required field consisting solely a special whitespace character.
The email address to which delegation should be granted is sent through a separate channel.