Define traffic light for exception groups. Press F1 for more information

How to fix this error?

This is where you use exception groups to define under which
circumstances materials are indicated by red, yellow, or green traffic
lights in the MRP list and the stock/requirements list.
Example:
You want yellow traffic lights to indicate materials with exception
messages for exception group 4, and red traffic lights to indicate
materials with exceptions messages for exception group 5.
You define the following:
,,,,,,,,,,Red,,,,Yellow,,Green
Exception group 4:,,,,,,X
Exception group 5:,,X

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

The traffic light for the material is set after the settings for all
days' supplies and all exceptions groups have been taken into
consideration.
Example:
A material with exception messages for exception group 4 and exception
group 5 would be indicated by a red traffic light in the example above,
as red traffic lights have a higher priority than the yellow traffic
lights.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.