This indicates that your user account does not have the relevant period posting rights to allocate to the year and period of the transaction or transactions in question.
Remember that if your system is set to allocate to the latest year/period of selected transactions, the system will check the year and period on the transactions you have selected, and allocation will take place in the furthest forward period and year out of the selected transactions (so if you select two transactions from current year and one from next year, allocation will take place in next year).
To check if your system is set to allocate to the latest year/period, go to:
System
Options
System Control Options
Transactions
You'll see the Method of Allocation option at the bottom of the window. If the system is defaulting to a future period, de-selecting this option should resolve the issue.
This can also be resolved by ensuring that your user account has the relevant future period rights to post into the relevant year and period. Please refer to our article on setting future period posting rights to set this up.
Once your user account has permission to post into the relevant year and period, you will then be able to complete your allocation.
If the above does not resolve the issue then if these transactions are partially allocated thencheck for the periods of those:
Click Creditors, Suppliers, Find
Enter the supplier code and press RETURN
Click Transactions
Select each of the transactions being selected in the allocations window in turn
Right-click and choose View Allocations
The latest allocation periods are shown against each and the allocation screen will not allow an allocation earlier than the latest of these allocation periods.