We were using Log4Net v1.2.13.0 with an application that targets .net framework 4 on windows server 2003, Below is the SmptAppender configuration (hiding our production values with xxxx). We were able to receive email on 'FATAL' log entry. <appender name="SmtpAppender" type="log4net.Appender.SmtpAppender"> <to value="xxxx" /> <from value="xxxx" /> <subject type="log4net.Util.PatternString" value="xxxx" /> <smtpHost value="xxxx" /> <username value="xxxx" /> <password value="xxxx" /> <authentication value="Basic" /><bufferSize value="5" /><lossy value="true" /><evaluator type="log4net.Core.LevelEvaluator"> <threshold value="FATAL" /> </evaluator><layout type="log4net.Layout.PatternLayout"> <conversionPattern value="%newline%date %-5level [%logger] %message%newline%exception%newline" /> </layout> </appender> We recently updated our application to use Log4Net v2.0.8, with the same configuration for SmptAppender . After this update, we stopped receiving emails. On enabling the internal log4Net logging, the below error was logged. log4net: Created Appender [SmtpAppender]log4net: Adding appender named [SmtpAppender] to logger [root].log4net: Hierarchy Threshold []log4net:ERROR [SmtpAppender] ErrorCode: GenericFailure. Failed in DoAppendSystem.TypeLoadException: Could not load type 'System.Security.Claims.ClaimsIdentity' from assembly 'mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'. at log4net.Core.LoggingEvent.get_UserName() at log4net.Core.LoggingEvent.FixVolatileData(FixFlags flags) in c:\log4net\tags\2.0.8RC1\src\Core\LoggingEvent.cs:line 1341 at log4net.Appender.BufferingAppenderSkeleton.Append(LoggingEvent loggingEvent) in c:\log4net\tags\2.0.8RC1\src\Appender\BufferingAppenderSkeleton.cs:line 483 at log4net.Appender.AppenderSkeleton.DoAppend(LoggingEvent loggingEvent) in c:\log4net\tags\2.0.8RC1\src\Appender\AppenderSkeleton.cs:line 317log4net: Shutdown called on Hierarchy [log4net-default-repository] If we revert back to Log4Net v1.2.13.0, we start receiving emails as expected. Please advise how can we resolve the issue with version 2.0.8.
Thanks and Regards Mohkam Singh
