Message type: E = Error
Message class:  CNV_OR_PE_GEN - Messages for generation functions 
Message number: 003
Message text: Object &1 already exists; creation is not possible
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_OR_PE_GEN003 indicates that there is an attempt to create an object (such as a project, a table, or a data structure) that already exists in the system. This error typically arises during data migration or conversion processes, particularly when using SAP's tools for data migration, such as the SAP S/4HANA Migration Cockpit or other conversion tools.
Cause: Duplicate Object: The most common cause is that the object you are trying to create already exists in the database or in the system. Incorrect Configuration: There may be a misconfiguration in the migration settings or parameters that leads to the attempt to create an object that is already present. Previous Migration Attempts: If a previous migration or conversion attempt was partially successful, it may have left behind objects that are now causing conflicts.
Solution: Check for Existing Objects: Use transaction codes like SE11 (Data Dictionary) or SE80 (Object Navigator) to check if the object
 Get instant SAP help. Sign up for our Free Essentials Plan.
Get instant SAP help. Sign up for our Free Essentials Plan. 
CNV_OR_PE_GEN002 DDIC object &1 is not active
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CNV_OR_PE_GEN001 Error during check of DDIC object &1 (see long text)
What causes this issue?  An unexpected error occurred while checking the object &V1&System Response  Error &V2&How to fix this error? ...
CNV_OR_PE_GEN004 Table &1 already has data; adjustment is not possible
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CNV_OR_PE_GEN005 Generation of object &1 failed (see long text)
What causes this issue?  The generation of object &V1& failed.System Response  Function &V2& ended with error code &V3&How to ...
Click on this link to search all SAP messages.