Error determining planning periods for Calendar 127

[KB_MANI]

Can any one help in understanding what would be issue from the message
"error determining planning periods for Calendar 127".
this comes during the run mrp list .
What would we need to do to correct the issue. Pl advise.

It looks like there should be some issue in Planning Calendar .


should we need to extend the validity period for the planning caledar.... and after doing this do we need to MRP to see the error correct in MRP list.