Positive values for revenues ("negative revenues") are not supported

What causes this issue?

For customer contract items like a sales order item or a contract item
in a customer project it is expected, that the amount for the total plan
revenue is a positive amount and that the amount of the cumulated actual
revenue with respect to the calculation period of the closing run is a
positive amount.
For the special case of a customer return item in sales, both the plan
revenue and the actual revenue have negative amounts.
Please note that in a journal entry item in financials positive costs
have positive amounts, but positive revenues have negative amounts.

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?

Please check the actual amount in a financial report. Sometimes it
happens that by mischance there is a credit memo which leads to this
situation temporarily for a certain calculation period of the closing
run. In this case you might apply a manual correction or you wait for
the closing run of the next period.
You also might check the plan values. It depends on the source of the
plan values which is used by revenue recognition, where this can be
checked.
You also might check the sources of revenue recognition. May be a
certain GL account or a condition type is not assigned.
IF &[SWITCH]S4H_DOCU_CLOUD& = 'X'.
For checking the sources you may use the app Revenue Recognition (Event
Based) , select detail, execute action evaluate, then explain
simulation.
ELSE.
For checking the sources you may use the support monitor, transaction
REV_REC_MON or REV_REC_SUP or the report FINS_TRR_ASS_RULE_DERIV_EXPL.
ENDIF.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.