It’s probably due to your file name configuration in the appender section of the Logback.xml file. Logback does not like relative file paths! Make sure that both your appender -> file value and the rollingPolicy -> fileNamePattern values have an absolute file path configured. For mine, I used the ${catalina.base} property so that our logs will show up in the tomcat logs directory, regardless of which server the application is deployed to.
...
<appender name="FILE" class="ch.qos.logback.core.rolling.RollingFileAppender">
<!-- Never use relative paths with logback! -->
<file>${catalina.base}/logs/my-application.log</file>
<append>true</append>
<rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
<!-- daily rollover -->
<!-- Never use relative paths with logback! -->
<fileNamePattern>${catalina.base}/logs/my-application.%d{yyyy-MM-dd}.log</fileNamePattern>
<!-- keep 30 days' worth of history -->
<maxHistory>30</maxHistory>
</rollingPolicy>
<encoder>
<pattern>%date %level [%thread] %logger{10} [%file:%line] %msg%n</pattern>
</encoder>
</appender>
...
Mindless... 