Reconciliation
Set Up RdN Reconciliation:
Open RdN Reconciliation - Setup with Assistance
Number Sequence

You need to create a number sequence for settlement in reconciliation. E.g. AF000001.
Other Settings

If you want to use one settlement number per run (automatic settlement), then you need to check this field (rare case).
Allow unsafe suggestions are used if you want to enable automatic settlement on entries that are not on the same date or the same amount. This can be risky.
It is related to the "Maximum Allowed Date Difference" field in automatic settlement. It is good to set 3D here as dates in the bank can differ by 1-2 days depending on whether it is a business day or weekend.