Message type: E = Error
Message class:  FI_E - Message Class for FM English Developers 
Message number: 018
Message text: Period &1/Fiscal Year &2 for &3 not open for FM posting in value type &4
Posting for the document of value type &V4& was attempted on a date
that has not been opened in FM.
The system issues an error message and will not allow you to continue with this transaction until the error is resolved.
To define open time intervals for FM postings, use the following
transactions:
<DS:TRAN.FMIR>Individual Maintenance of Open Time Intervals</>
<DS:TRAN.FMMI>Mass Maintenance of Open Time Intervals</>
Error message extract from SAP system. Copyright SAP SE.
The SAP error message FI_E018 indicates that a specific period and fiscal year are not open for Financial Management (FM) posting in a particular value type. This error typically arises when you attempt to post a transaction in a period that has not been opened for posting in the FM module.
Cause: Period Not Open: The specified period and fiscal year are not open for FM postings. This can happen if the period is closed in the FM settings. Value Type Restrictions: The value type you are trying to use may have specific restrictions or may not be allowed for posting in the current period.
Configuration Issues: There may be configuration settings in the FM module that restrict postings to certain periods or fiscal years.
Solution: Open the Period: Navigate to the transaction code FMAVCR01 (or the relevant transaction for your version) to check the status of the periods. Open the required period for FM postings if it
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