Only &2 decimal places are defined for unit of measure &1

What causes this issue?

For values managed in the &V1& unit of measure, a rounding to &V2&
decimal places has been specified in Customizing. The order quantity
entered shows a higher level of exactness.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Check the entry.
The value entered may lead to problems in subsequent applications.
Difficulties are caused in particular by the late conversion of a
planned order in SAP R/3 with an unchanged quantity, into a production
or process order.
Processing of this type of order is stopped in several places by an
error message (message RU 303).

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.