Can delivery date for material & be kept? Realistic date: &

What causes this issue?

The date is the delivery date taking int account
<GL:planned_delivery_time>planned delivery time</> in the
<GL:material_master>material master</>
purchasing department processing time from table 399D
goods receipt processing time in the material master or in the item

How to fix this error?

INCLUDE NA_T160M
You can change the delivery date specified and enter a realistic
delivery date &V2&.

Error message extract from SAP system. Copyright SAP SE.