The unit of measure specified does not exist for the language &

What causes this issue?

You have chosen <LS>New selection</> for a unit of measure that is not
defined in the logon language &V1&.

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?

Enter a unit of measure that is allowed in the logon language.
Note
To check which units of measure are allowed for the material, choose
<LS>Extras</> -> <LS>Units allowed</>.

Error message extract from SAP system. Copyright SAP SE.