Message type: E = Error
Message class:  BCS_MAIL_CONFIG - Mail Configuration Messages 
Message number: 015
Message text: Cannot determine subaccount
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 BCS_MAIL_CONFIG015: Cannot determine subaccount typically occurs in the context of the Business Communication Services (BCS) when there is an issue with the configuration of email settings, particularly related to the subaccount settings for sending emails.
Cause: Missing Configuration: The subaccount for the email sending process may not be configured in the system. Incorrect Settings: The settings for the email account or the subaccount may be incorrect or incomplete. Authorization Issues: The user or the system may not have the necessary authorizations to access the subaccount. System Settings: There may be issues with the overall system configuration related to email services.
Solution: Check Configuration: Go to the transaction code SCOT (SAPconnect Administration). Check the configuration for the SMTP node and ensure that the subaccount is correctly defined. Ensure that the email address and other relevant settings are correctly configured. Define Subaccount: If the subaccount is not defined, you may need to create it. This can typically be done in
 Get instant SAP help. Sign up for our Free Essentials Plan.
Get instant SAP help. Sign up for our Free Essentials Plan. 
BCS_MAIL_CONFIG014 Password identifier is initial.
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
BCS_MAIL_CONFIG013 Password is inital.
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
BCS_MAIL_CONFIG016 Function not supported
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
BCS_MEDIUM000 ----------------Runtime to 200----------------------------------------
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.