In order to verify parent accounts, Pupil Progress requires students or parents to enter the student's date of birth. This is the last of a series of security measures which verify that the right student is linked to the correct app account.
If a parent is associated with students that don't have a date of birth, they will be marked as Non-invitable. You will need to add the date of birth before you can invite them.
How do I add a Date of Birth to the students?
If you are synced via Groupcall, this field will be auto-populated, so if this is blank for a student you will need to update it on your MIS.
If students are manually managed, click on the 3-dot button and select Edit Student. Add a date of birth and save changes.