Parameter &1 not found

What causes this issue?

The system has tried to start a function module. However, the parameter
&V1&, which is required to call the function module, is missing.

System Response

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

How to fix this error?

Add a parameter in the format &V1&=<value> to the function call.

Error message extract from SAP system. Copyright SAP SE.