The following errors frequently occurrs. 
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05/14 09:05:33.436  INFO (http-37080-1:) - [Layer7Reports general] -- Using interval=900000
05/14 09:05:33.440 ERROR (http-37080-1:) - [Layer7Reports general] -- java.sql.SQLException: Already closed.
        at org.apache.tomcat.dbcp.dbcp.PoolableConnection.close(PoolableConnection.java:114)
        at org.apache.tomcat.dbcp.dbcp.PoolingDataSource$PoolGuardConnectionWrapper.close(PoolingDataSource.java:191)
        at com.l7tech.portal.reports.MetricsReportGenerator.a(Unknown Source)
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What does it mean?
Is there a way to solve it?

CA API Developer Portal - 3.x

This error is indicating a temporary communication problem between the Portal and the MySQL database. 
It can be ignored