Check the settings for checking group &1 and checking rule &2

What causes this issue?

The system could not determine any checking rules / a valid checking
group for the availability check.

System Response

In order to perform the dynamic availability check, the following two
parameters need to be maintained in the system:
Checking rule in Customizing
Checking rule in material master
The <ZH>checking rule</> controls which requirements and receipts
elements are used when the availability check is performed and whether
the replenishment lead time is to be considered in the chack or not.
You can use the various checking rules to define different rules for
the availability check in the business applications (Sales and
Distribution, Material Requirements Planning, Production Order
Management, Inventory Management). The checking rules of the individual
applications are assigned to the checking groups in Customizing. If an
availability check is to be carried out for a material, then the
required <ZH>checking group</> is assigned to the material in the
material master record. The system uses the checking group to find the
valid checking rule(s) for each application.

How to fix this error?

Proceed as follows:
In Customizing for Material Requirements Planning (or Sales and
Distribution, Production Order Management, Inventory Management), check
to see whether the cheking rule has been assigned plant-specifically or
MRP-group-specifically. (In Customizing for Material Requirements
Planning you can find the checking rule under: <LS>Procurement
Proposals -> Planned Orders -> Define availability check for
components</>
Assign a checking rule as required to the corresponding plant or to the
MRP group used to plan the material.

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

&Note&
You can find more information about the availability check in Material
Requirements Planning in the IMG chapter: "Define availability check
for components".
Check to see whether a checking group has been entered for the
component in the material master record (MRP screen 2 or sales/plant
screen, <LS>Availability check</> field).
Maintain a checking group if necessary.
If you do not wish to perform an availability check, assign the
checking group "No availability check" in the material master record.

Error message extract from SAP system. Copyright SAP SE.