Unable to cancel a pick line.

Unable to cancel a pick line. I receive the error message: Activities in process exist. Any suggestions would be appreciated. Thanks.

Is this WHS? WMSII? WMS? A sales order, a production order, a transfer order a purchase return?

We are on AX2012, R3, CU8

Does not really help though - which picking list during which process?

Sales order picking list. We have 110 pounds that is a deliver remainder but I cannot cancel the pick line or deliver remainder to finish the order.