Message type: E = Error
Message class:  CNV_PE - General messages for posting engine 
Message number: 303
Message text: LDDEF totals Customizing
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_PE303 "LDDEF totals Customizing" typically occurs during the execution of a data migration or conversion process, particularly when using the SAP S/4HANA Migration Cockpit or similar tools. This error indicates that there is an issue with the configuration of the totals for the logical data definition (LDDEF) in the system.
Cause: Missing Configuration: The error often arises when the necessary customizing settings for the totals in the logical data definition are not properly configured or are missing. Inconsistent Data: There may be inconsistencies in the data that is being migrated, which do not align with the expected totals configuration. Incorrect Mapping: The mapping of fields between the source and target systems may not be correctly defined, leading to discrepancies in totals. Version Compatibility: The error can also occur if there are compatibility issues between the versions of the source and target systems.
Solution: Check Customizing Settings: Navigate to the relevant customizing transaction (usually
 Get instant SAP help. Sign up for our Free Essentials Plan.
Get instant SAP help. Sign up for our Free Essentials Plan. 
CNV_PE302 LDAMTF totals Customizing
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CNV_PE301 Area &1 and WSPOS &2 successfully synchronized
What causes this issue?  Area ID &V3& Workset &V4&System Response  The system issues an error message and will not allow you to contin...
CNV_PE304 Knowledge base of known applications is missing (see long text)
What causes this issue?  To check which ledger totals tables are supported for a transfer, the tool requires certain information within its knowledge ...
CNV_PE305 Posting key info already present for area &1 and target &2
What causes this issue?  The data is already present.System Response  By default the data is not overwritten.How to fix this error?  Check if this beh...
Click on this link to search all SAP messages.