Message type: E = Error
Message class:  OIJ_RU - Messages for TSW-ETRAN integration 
Message number: 304
Message text: Enter Special G/L Indicator
Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of messages in the SAP system have a message text, however this is frequently insufficient to comprehend or resolve the problem.
To make things easier, more detailed information is frequently added to describe the issue, how to fix it, and the necessary steps or configuration modifications.
Unfortunately, there isn't any extra information in this error notice.
First, use our AnswerBot below to get a possible cause and solution (requires a premium subscription).
Also, review the in-depth Common Questions & Answers listed below; you could discover a solution there or be able to connect with others who have faced similar challenges.
You can also try searching the SAP support portal (support.sap.com) but you need a special user ID to access it. It is possible that an SAP support note exists that provides additional details about the mistake or even steps for fixing it.
The SAP error message OIJ_RU304, which prompts the user to "Enter Special G/L Indicator," typically occurs in the context of financial transactions within the SAP system, particularly when dealing with special general ledger (G/L) accounts. This error indicates that the system requires a special G/L indicator to be specified for the transaction being processed.
Cause: Missing Special G/L Indicator: The transaction you are trying to execute requires a special G/L indicator, but it has not been provided in the transaction data.
Configuration Issues: The configuration for the special G/L accounts may not be set up correctly, or the account being used may not be designated for special G/L transactions. Transaction Type: The type of transaction being processed may inherently require a special G/L indicator, such as down payments, guarantees, or other special transactions.
Solution: Enter the Special G/L Indicator: When prompted with the error message, you should enter the appropriate special G/L indicator in the relevant
 Get instant SAP help. Sign up for our Free Essentials Plan.
Get instant SAP help. Sign up for our Free Essentials Plan. 
OIJ_RU303 Enter Posting Key
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
OIJ_RU302 Enter either field name or text ID; do not enter both
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
OIJ_RU400 Cannot find service code in invoice
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
OIJ_RU401 Cannot find external ticket number in invoice
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
Click on this link to search all SAP messages.