Message type: E = Error
Message class:  CNV_PE_DTL -  
Message number: 056
Message text: Sender RFC destination not present in MWB subproject &1
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_PE_DTL056 indicates that there is an issue with the sender RFC (Remote Function Call) destination not being present in the specified Migration Workbench (MWB) subproject. This error typically arises during data migration processes, particularly when using the SAP Migration Workbench for data transfer.
Cause: Missing RFC Destination: The specified RFC destination that is supposed to be used for communication between systems is not defined in the system or is not correctly configured. Incorrect Subproject Configuration: The subproject in the Migration Workbench may not have the necessary settings or configurations to recognize the sender RFC destination. Authorization Issues: There may be authorization issues preventing the system from accessing the RFC destination. System Configuration: The system may not be properly configured to handle the RFC calls, or the destination may have been deleted or incorrectly set up.
Solution: Check RFC Destination: Go to transaction SM59 in the SAP GUI. Verify that the required RFC destination is defined
 Get instant SAP help. Sign up for our Free Essentials Plan.
Get instant SAP help. Sign up for our Free Essentials Plan. 
CNV_PE_DTL055 Migration object &1 exists already
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CNV_PE_DTL054 Migration object &1 does not exist
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CNV_PE_DTL059 Mass transfer load status is reset successfully
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CNV_PE_DTL061 Root table of data model not found
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.