Message type: E = Error
Message class:  CNV_CMIS_M - Message class for CMIS Migration 
Message number: 015
Message text: Value & exists already for this field
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_CMIS_M015 indicates that a value already exists for a specific field in the context of a data migration or conversion process. This error typically arises during the execution of a data migration project, particularly when using the SAP Conversion Tools or during the data import process.
Cause: Duplicate Values: The most common cause of this error is that the value being inserted or updated already exists in the target table for the specified field. This can happen if: The data being migrated contains duplicates. The target system already has existing records with the same value in the specified field. Data Integrity Constraints: The field may have unique constraints or primary key constraints that prevent duplicate entries. Incorrect Mapping: There may be an issue with how the data is mapped from the source to the target, leading to attempts to insert duplicate values.
Solution: Identify Duplicates: Check the source data for duplicates. You can use
 Get instant SAP help. Sign up for our Free Essentials Plan.
Get instant SAP help. Sign up for our Free Essentials Plan. 
CNV_CMIS_M014 An identical mapping entry already exists; remove or change this entry
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CNV_CMIS_M013 Rule & is referenced by at least one domain and may not be deleted
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CNV_CMIS_M016 Enter a domain value
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CNV_CMIS_M017 Enter an existing rule name
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.