Message type: E = Error
Message class:  CNV10400 - Messages for package 10400 (characteristics) 
Message number: 304
Message text: Active package cannot be set to initial
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 CNV10400304 indicates that an active package cannot be set to the initial state. This typically occurs in the context of 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: The error usually arises due to one of the following reasons: Active Package: The package you are trying to set to initial is currently active, meaning it is in use or has been processed. Active packages cannot be reset to an initial state because they may contain data or configurations that are currently being utilized. Dependencies: There may be dependencies or references to the active package in other processes or configurations, preventing it from being reset. Authorization Issues: Sometimes, the user may not have the necessary authorizations to change the status of the package.
Solution: To resolve the error, you can try the following steps: Check Package Status: Verify
 Get instant SAP help. Sign up for our Free Essentials Plan.
Get instant SAP help. Sign up for our Free Essentials Plan. 
CNV10400303 Active package not yet set
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CNV10400302 No CNVFIELDS entries for package &1 found
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CNV10400305 Package with ID & does not exist in this client
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CNV10400306 No INCLUDES found for package &1
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.