Message type: E = Error
Message class:  CNV_20200_CHECK - Messages for check functions (company code merge) 
Message number: 064
Message text: Company code &1 assigned to company &2
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_20200_CHECK064 typically occurs during data migration or conversion processes, particularly when using the SAP S/4HANA Migration Cockpit or similar tools. This error indicates that there is an issue with the assignment of company codes to companies in the system.
Cause: The error message "Company code &1 assigned to company &2" suggests that there is a mismatch or inconsistency in the assignment of company codes to companies. This can happen due to several reasons, such as: Incorrect Configuration: The company code may not be correctly assigned to the company in the configuration settings. Data Migration Issues: During data migration, the mapping of company codes to companies may not have been done correctly. Duplicate Entries: There may be duplicate entries or conflicts in the assignment of company codes to companies. Missing Data: The necessary data for the company code or company may be missing or incomplete.
Solution: To resolve this error, you can take the following
 Get instant SAP help. Sign up for our Free Essentials Plan.
Get instant SAP help. Sign up for our Free Essentials Plan. 
CNV_20200_CHECK063 No differences in selected fields of G/L account master data found
What causes this issue?  All fields of G/L account master data except the fields ERDATand ERNAM and critical fields, such as XOPVW, XSALH, MITHKZ, WAR...
CNV_20200_CHECK062 There are differences in the G/L account master data
What causes this issue?  There are differences in the G/L account master data that are not critical regarding the merge, but can seriously affect busi...
CNV_20200_CHECK065 Other CoCodes which are assigned to a particpating credit control area:
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CNV_20200_CHECK066 All participating company codes have no company assignment
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.