Message type: E = Error
Message class:  CUMTX - Variant Configuration - Master Data Maintenance 
Message number: 690
Message text: Use transaction & to maintain variant tables
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 CUMTX690 indicates that there is an issue related to maintaining variant tables in the SAP system. This error typically arises when a user attempts to access or modify a variant that is not properly defined or is missing in the system.
Cause: Missing Variants: The variant you are trying to access may not exist in the system. Authorization Issues: The user may not have the necessary authorizations to maintain or access the variant tables. Incorrect Transaction Code: The transaction code used may not be the correct one for maintaining the variant tables. Technical Issues: There could be underlying technical issues or inconsistencies in the database.
Solution: Check Transaction Code: Ensure that you are using the correct transaction code to maintain the variant tables. The message suggests using a specific transaction code (usually indicated in the error message) to access the variant maintenance screen. Maintain Variants: Use the appropriate transaction (like SE38 for ABAP programs
 Get instant SAP help. Sign up for our Free Essentials Plan.
Get instant SAP help. Sign up for our Free Essentials Plan. 
CUMTX687 Entries in planning table & deleted
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CUMTX683 Combination is used in statistics and cannot be deleted
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CUMTX691 Use transaction & to maintain planning tables
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CUMTX692 New engineering change management is not yet released for variant tables
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.