Что это означает? Почему оно происходит?

[20.10.19 19:49:25] L2DatabaseFactory: Failed to retrieve database connection!
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
	at sun.reflect.GeneratedConstructorAccessor73.newInstance(Unknown Source)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
	at com.mysql.jdbc.Util.handleNewInstance(Util.java:425)
	at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:990)
	at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:342)
	at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2188)
	at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2221)
	at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2016)
	at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:776)
	at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
	at sun.reflect.GeneratedConstructorAccessor71.newInstance(Unknown Source)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
	at com.mysql.jdbc.Util.handleNewInstance(Util.java:425)
	at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:386)
	at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:330)
	at org.apache.commons.dbcp.DriverConnectionFactory.createConnection(DriverConnectionFactory.java:38)
	at org.apache.commons.dbcp.PoolableConnectionFactory.makeObject(PoolableConnectionFactory.java:582)
	at org.apache.commons.pool.impl.GenericObjectPool.borrowObject(GenericObjectPool.java:1148)
	at org.apache.commons.dbcp.AbandonedObjectPool.borrowObject(AbandonedObjectPool.java:79)
	at org.apache.commons.dbcp.PoolingDataSource.getConnection(PoolingDataSource.java:106)
	at org.apache.commons.dbcp.BasicDataSource.getConnection(BasicDataSource.java:1044)
	at ru.catssoftware.L2DatabaseFactory.getConnection(L2DatabaseFactory.java:128)
	at ru.catssoftware.gameserver.util.QueuedItems$1.run(QueuedItems.java:76)
	at java.lang.Thread.run(Thread.java:748)
Caused by: java.net.ConnectException: Connection refused (Connection refused)
	at java.net.PlainSocketImpl.socketConnect(Native Method)
	at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
	at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
	at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
	at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
	at java.net.Socket.connect(Socket.java:589)
	at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:211)
	at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:301)
	... 20 more

2019-10-22T03:06:59.940805Z 4807 [Warning] IP address 'XXX.XX.XX.XX' could not be resolved: Temporary failure in name resolution
2019-10-22T03:07:00.178937Z 4807 [Note] Access denied for user 'root'@'XXX.XX.XX.XX' (using password: YES)
2019-10-22T03:07:01.732520Z 4808 [Warning] IP address 'XXX.XX.XX.XX' could not be resolved: Temporary failure in name resolution
2019-10-22T03:07:04.860964Z 4808 [Note] Access denied for user 'root'@'XXX.XX.XX.XX' (using password: YES)
2019-10-22T03:07:05.380610Z 4809 [Warning] IP address 'XXX.XX.XX.XX' could not be resolved: Temporary failure in name resolution
2019-10-22T03:07:05.627374Z 4809 [Note] Access denied for user 'root'@'XXX.XX.XX.XX' (using password: YES)
2019-10-22T03:07:07.143244Z 4810 [Warning] IP address 'XXX.XX.XX.XX' could not be resolved: Temporary failure in name resolution
2019-10-22T03:07:07.379718Z 4810 [Note] Access denied for user 'root'@'XXX.XX.XX.XX' (using password: YES)
2019-10-22T03:07:09.072248Z 4811 [Warning] IP address 'XXX.XX.XX.XX' could not be resolved: Temporary failure in name resolution
2019-10-22T03:07:09.317083Z 4811 [Note] Access denied for user 'root'@'XXX.XX.XX.XX' (using password: YES)
2019-10-22T03:07:10.291268Z 4812 [Warning] IP address 'XXX.XX.XX.XX' could not be resolved: Temporary failure in name resolution
2019-10-22T03:07:13.500931Z 4812 [Note] Access denied for user 'root'@'XXX.XX.XX.XX' (using password: YES)
2019-10-22T03:07:14.058111Z 4813 [Warning] IP address 'XXX.XX.XX.XX' could not be resolved: Temporary failure in name resolution
2019-10-22T03:07:14.302534Z 4813 [Note] Access denied for user 'root'@'XXX.XX.XX.XX' (using password: YES)
2019-10-22T03:07:14.841044Z 4814 [Warning] IP address 'XXX.XX.XX.XX' could not be resolved: Temporary failure in name resolution
2019-10-22T03:07:15.077352Z 4814 [Note] Access denied for user 'root'@'XXX.XX.XX.XX' (using password: YES)
2019-10-22T03:07:15.602896Z 4815 [Warning] IP address 'XXX.XX.XX.XX' could not be resolved: Temporary failure in name resolution
2019-10-22T03:07:15.850999Z 4815 [Note] Access denied for user 'root'@'XXX.XX.XX.XX' (using password: YES)
2019-10-22T03:10:21.237410Z 4823 [Note] Got an error reading communication packets
2019-10-22T08:53:17.063622Z 5557 [Warning] IP address 'XXX.XX.XX.XX' has been resolved to the host name '25.XXX.XX.XXX.adsl-pool.jlccptt.net.cn', which resembles IPv4-address itself.
2019-10-22T08:53:17.066028Z 5557 [Note] Got an error reading communication packets
2019-10-22T11:10:25.623969Z 4825 [Note] Aborted connection 4825 to db: 'NAMEBASE' user: 'NAME' host: 'localhost' (Got timeout reading communication packets)
2019-10-22T11:10:30.923995Z 4827 [Note] Aborted connection 4827 to db: 'NAMEBASE' user: 'NAME' host: 'localhost' (Got timeout reading communication packets)
2019-10-22T11:10:31.371982Z 4828 [Note] Aborted connection 4828 to db: 'NAMEBASE' user: 'NAME' host: 'localhost' (Got timeout reading communication packets)
2019-10-22T12:41:25.518742Z 6044 [Warning] IP address 'XXX.XX.XX.XX' could not be resolved: Name or service not known
2019-10-22T12:41:35.528593Z 6044 [Note] Got timeout reading communication packets
2019-10-22T15:58:14.193809Z 6493 [Warning] Host name '34-128.XXX.XXX.serverhubrdns.in-addr.arpa' could not be resolved: Name or service not known
2019-10-22T15:58:24.202019Z 6493 [Note] Got timeout reading communication packets
2019-10-22T17:19:46.322993Z 6374 [Note] Aborted connection 6374 to db: 'NAMEBASE' user: 'NAME' host: '109.196.134.84' (Got timeout reading communication packets)
2019-10-22T19:28:51.800131Z 6993 [Note] Aborted connection 6993 to db: 'NAMEBASE' user: 'NAME' host: 'localhost' (Got an error reading communication packets)
2019-10-22T19:28:51.800204Z 6966 [Note] Aborted connection 6966 to db: 'NAMEBASE' user: 'NAME' host: 'localhost' (Got an error reading communication packets)
2019-10-22T19:28:51.800338Z 6994 [Note] Aborted connection 6994 to db: 'NAMEBASE' user: 'NAME' host: 'localhost' (Got an error reading communication packets)
2019-10-22T19:28:51.800888Z 6918 [Note] Aborted connection 6918 to db: 'NAMEBASE' user: 'NAME' host: 'localhost' (Got an error reading communication packets)
2019-10-22T19:29:05.708578Z 7006 [Note] Got an error reading communication packets
2019-10-22T19:29:08.848003Z 7009 [Note] Aborted connection 7009 to db: 'NAMEBASE' user: 'NAME' host: 'localhost' (Got an error reading communication packets)
2019-10-22T19:29:21.836540Z 7013 [Note] Got an error reading communication packets
2019-10-22T19:51:06.036879Z 7086 [Note] Got an error reading communication packets