Planned delivery time is 0 for ext. procured material

What causes this issue?

You are creating a master record for a material that is to be procured
externally. However, you have not entered a planned delivery time.
A planned delivery time of zero only makes sense if the material can be
procured in less than a day. This is possibly the case, for example,
when stock is transferred from one plant to another.

How to fix this error?

INCLUDE NA_SACHVERHALT

Error message extract from SAP system. Copyright SAP SE.