92f0c79b_j_2_Appenders___Apache_Log4j_2_SMTPAppender_Parameters_Description
[Parameter Name] ignoreExceptions [Type] boolean [Description] 
The default is true, causing exceptions encountered while appending events to be internally logged and then ignored. When set to false exceptions will be propagated to the caller, instead. You must set this to false when wrapping this Appender in a FailoverAppender.
Log4j – Log4j 2 Appenders - Apache Log4j 2