Enter change number - BOM has history requirement

What causes this issue?

You want to change a particular BOM but you have not entered a change
number.
This error message appears for the following reasons:
Once a BOM has been changed with history (with a change number), it can
only be changed with history.
Options set via Customizing (BOMs) determine that BOMs with a
particular usage and status are to be changed with history.

How to fix this error?

Check your entries.
If your entries for the BOM are correct, enter a change number.
The following factors should be taken into account when choosing a
change number:
which object types or which objects can be changed using this change
number;
the validity of the change number ;
the reason for the change.

Error message extract from SAP system. Copyright SAP SE.