Customer-specific function cannot be started

What causes this issue?

There are some prerequisites to be fullfilled before the customer
function on the standard UI can be used.

System Response

The customer-specific function cannot be started.

How to fix this error?

Check queue processing for inspection results. The result has to be
available in ERP.
Check if inspection document or inspection item has been decided.
Check the RFC destination.

Procedure for System Administrators

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

Error message extract from SAP system. Copyright SAP SE.