Message type: E = Error
Message class:  FB - Batch Programs 
Message number: 696
Message text: Mail to &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 FB696 ("Mail to &1") typically indicates that there is an issue related to sending an email notification within the SAP system. This error can occur in various contexts, such as during the processing of financial documents or when executing certain transactions that involve email notifications.
Cause:
Email 
Configuration Issues: The SAP system may not be properly configured to send emails. This could be due to missing or incorrect settings in the SAPconnect configuration.
Recipient Address Issues: The email address specified (represented by &1 in the error message) may be invalid, missing, or incorrectly formatted.
SMTP Server Issues: There may be connectivity issues with the SMTP server that SAP is trying to use to send the email.
Authorization Issues: The user or the system may not have the necessary authorizations to send emails.
System Errors: There could be temporary system errors or issues with the email server.
Solution:
Check SAPconnect Configuration:
Go to transaction code SCOT Get instant SAP help. Sign up for our Free Essentials Plan.
Get instant SAP help. Sign up for our Free Essentials Plan. 
FB695 Fax ID &1 to Number &2 &3
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
FB694 Vendor & has a different head office in corr. co. code than in co. code &
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
FB697 Bank details & / & are active more than once in bank account management
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
FB698 Bank details & / & occur more than once in bank account management
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.