Task list and reference operation set belong to different company codes

What causes this issue?

You attempted to include a reference operation set which belongs to a
different company code as the routing.
The plant determines the company code of a task list.
You can generally use cross-company code references in a routing.
However, a company code check is set up in your system for the fiscal
year.

How to fix this error?

Include a reference operation set whose plant belongs to the same
company code as the plant from your routing.

Error message extract from SAP system. Copyright SAP SE.