DEX Portal File Processing returns the following error:
Field value is outside the acceptable range (0-999). Check unidentified attendance values on related sessions.
The TOTAL UNIDENTIFIED CLIENTS for a single case is calculated based on the sum of unidentified clients in all sessions related to that case.
For example if you have 10 sessions and in each one you nominated 100 unidentified clients the total for the case will be 1000 which is more than DEX allows for a single case (999).
Edit one of the sessions that have a very high number and reduce the number until the total for the case falls under 999.
If you coordinate a group activity for very long period, you may want to consider duplicating the case, closing the old one and start using a new one in each reporting period or at least at the end of the year.
This will ensure the total number of unidentified attendees remains low.
The Activity (case) record must be edited and saved to recalculate the unidentified attendee field.