STO DN Unable to delete , error WMS already confirmed

Hi Experts,

We have STO PO which needs to be deleted as it is no longer required.

But for this STO, DN was created, and TO also confirmed.

We followed the below steps, didn't work.

Created DN For STO-VL10B

Created TO-LT03

Confirmed TO-LT12 (Stock moved to physical Bin to 916 Bin)

Checked the Stock LT26

Return to stock from Delivery -LT0G

Confirm TO -LT12 (Stock is back to Physical Bin)

When try to delete DN we are getting error “Confirmation from WMS already performed; You cannot delete item 1“

Kindly check and share us your advice on this.