Meter reading unit allocated to main MR unit

What causes this issue?

You have allocated the current meter reading unit &V1& to main meter
reading unit &V2&. The street route for the current meter reading unit
&V1& must therefore be added to the street route of main meter reading
unit &V2&.

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?

To adjust the street route of main meter reading unit &V1&, choose
<ZH>Maintain street route</> and enter the enhancements via the current
meter reading unit &V2&.

Error message extract from SAP system. Copyright SAP SE.