What you're seeing. Either Finalise journal is greyed out, or selecting it returns "Cannot finalise journal due to compliance rule violations".

Why it happens. Three different causes:

Greyed out, sections incomplete — every section the team writes needs content.
Greyed out, confirmation not ticked — the accuracy confirmation is required.
Refused with a rule message — your company has a compliance rule that blocks finalisation while something is outstanding for that young person on that date. The message names the rule.

How to fix it. For the first two, complete the sections and tick the box — note that once a day is submitted, staff can no longer edit sections, so an incomplete one needs a manager decision. For the third, clear the item the rule names, then finalise again.

Who can fix it. You, unless the rule itself is wrong — a company admin owns the rule set.