Message type: E = Error
Message class:  CNV_10520 - Conversion module of FI-CA FIKEY-logic 
Message number: 003
Message text: &1 entries found in FI-CA table DFKKSUM
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 CNV_10520003 indicates that there are entries found in the FI-CA (Contract Accounts Receivable and Payable) table DFKKSUM that may be causing issues during a data migration or conversion process. This error typically arises during the execution of a migration project, particularly when using the SAP S/4HANA Migration Cockpit or similar tools.
Cause: The error message CNV_10520003 is triggered when the system detects that there are existing entries in the DFKKSUM table, which is used for storing summary data related to contract accounts. This can happen for several reasons, including: Existing Data: The DFKKSUM table contains data that is not compatible with the migration process, possibly due to previous transactions or configurations. Inconsistent Data: There may be inconsistencies in the data that prevent the migration from proceeding smoothly. Incomplete Cleanup: Prior to migration, certain cleanup activities may not have been performed, leaving residual data in the FI-CA tables.
Solution: To resolve the CNV_10520003 error,
 Get instant SAP help. Sign up for our Free Essentials Plan.
Get instant SAP help. Sign up for our Free Essentials Plan. 
CNV_10520002 There are no relevant mappings to be checked for table DFKKSUM
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CNV_10520001 &1 &2 &3 &4
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CNV_10520004 No entries found in FI-CA table DFKKSUM for FIKEY &1
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CNV_10520005 No duplicates found in structure of DFKKSUM after simulation conversion
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.