Message type: E = Error
Message class:  RSTT0 - Trace Tool: Message Class Engine Layer 
Message number: 098
Message text: Reference data variant already exists
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 RSTT0098, which states "Reference data variant already exists," typically occurs in the context of the SAP system when you are trying to create or modify a variant for a report or a transaction, and a variant with the same name already exists in the system.
Cause: Duplicate Variant Name: The most common cause of this error is that you are attempting to create a new variant with a name that is already in use by another variant in the same context (e.g., for the same report or transaction). System Configuration: In some cases, this could also be due to system configuration issues or inconsistencies in the variant management settings.
Solution: To resolve the RSTT0098 error, you can take the following steps: Check Existing Variants: Go to the transaction or report for which you are trying to create the variant. Use the variant management option (usually accessible via the "Variants" button or by pressing F4)
 Get instant SAP help. Sign up for our Free Essentials Plan.
Get instant SAP help. Sign up for our Free Essentials Plan. 
RSTT0097 Unable to process method &1 (&2) due to invalid interface
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
RSTT0096 Unable to process function module &1 (&2) due to invalid interface
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
RSTT0099 Select a row
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
RSTT0100 Test objects of trace '&1' ('&2') locked. Execution postponed
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.