Three common causes
First, capacity: the person approving does not meet the defined conditions. Second, timing: the approval window was missed. Third, record mismatch: the person's record does not support the capacity they have taken on.
Where to start
The error shown on screen is usually the consequence, not the cause. Check the person's record first, then the capacity, then the timing. If all three are right, the problem really is on the transmission side.
Proceeding with evidence
The date of each attempt, the response received and the correction made are recorded. Repeated attempts without records lead to repeating the same mistake unnoticed.
If the window closes
Where the approval window was missed, the process runs again from the start; waiting is not a solution and the time that passes counts as unassigned.
In Optifora
The assignment record shows capacity, timing and approval status together; it names what is missing and takes the correction to the relevant record's screen.