Message type: E = Error
Message class:  HRGB_GBRTI - Messages for RTI 
Message number: 100
Message text: Payment Month Number or Payment Week Number is mandatory
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The SAP error message HRGB_GBRTI100 indicates that either the Payment Month Number or the Payment Week Number is mandatory but has not been provided in the relevant payroll or payment processing context. This error typically arises in the context of payroll processing, particularly in the UK payroll module.
Cause: Missing Data: The error occurs when the system expects either a Payment Month Number or a Payment Week Number to be specified, but neither has been provided.
Configuration Issues: There may be configuration settings in the payroll module that require these fields to be filled out for certain payroll runs. Incorrect Payroll Run Type: The payroll run type may not be set correctly, leading to the system expecting different parameters.
Solution: Check Input Data: Ensure that the Payment Month Number or Payment Week Number is correctly filled in the payroll processing screen. This is usually found in the payroll run parameters. Review Payroll Configuration: Check the configuration settings
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