Message type: E = Error
Message class:  WB2B_CS - Trading Contract: Contract Matching and Settlement 
Message number: 405
Message text: Matching sub key data not found for Group & from & (Side: &)
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 WB2B_CS405 indicates that there is a problem with matching sub-key data in the context of a business transaction, typically related to the configuration of the system or the data being processed. This error often arises in the context of SAP's Business-to-Business (B2B) integration scenarios, particularly when dealing with master data or transactional data that requires specific keys to match.
Cause: The error message "Matching sub key data not found for Group & from & (Side: &)" generally occurs due to one or more of the following reasons: Missing Data: The required sub-key data (like customer, vendor, or material information) is not available in the system for the specified group or side.
Configuration Issues: There may be a misconfiguration in the B2B settings or in the master data settings that prevents the system from finding the necessary matching keys. Data Inconsistency: There could be inconsistencies in the data being processed, such as
 Get instant SAP help. Sign up for our Free Essentials Plan.
Get instant SAP help. Sign up for our Free Essentials Plan. 
WB2B_CS404 Matching sub key data not found for Group & and Matching Type & (Side: &)
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
WB2B_CS403 Matching key data not found for Matching Group &1 and Matching Type &2
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
WB2B_CS406 Matching type should not be blank. Please set & to call &
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
WB2B_CS407 Side should not be blank. Please set & to call &
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.