Message type: E = Error
Message class:  CNV_20700 - Material number conversion 
Message number: 229
Message text: No read only field found for Object Id &1 and Structure &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_20700229 typically occurs during data migration or conversion processes, particularly when using the SAP S/4HANA Migration Cockpit or other data migration tools. This error indicates that the system is unable to find a read-only field for a specified Object ID and Structure.
Cause: Missing Configuration: The error may arise if the configuration for the data migration object is incomplete or incorrect. The system expects certain fields to be defined as read-only, but they are either missing or not properly configured. Data Model Changes: If there have been changes in the data model (for example, during an upgrade or migration), the expected fields may no longer exist or may have been renamed. Incorrect Mapping: The mapping of fields between the source and target systems may not be set up correctly, leading to the system being unable to identify the necessary fields. Authorization Issues: Sometimes, the user executing the migration may not have
 Get instant SAP help. Sign up for our Free Essentials Plan.
Get instant SAP help. Sign up for our Free Essentials Plan. 
CNV_20700228 Conversion relevant field &1 found in structure &2 of field &3
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CNV_20700227 Object Id &1
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CNV_20700230 Dependent field &1
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CNV_20700231 No Conversion is required
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.