12:39:41 [INFO] [_Kuberq] <-> ServerConnector [lobby] has connected
12:39:41 [SEVERE] [ChangeSkin] Failed to save preferences
com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Duplicate entry '87f004fd114d3cac94093825618180d0' for key 'UUID'
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
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.Util.getInstance(Util.java:408)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:936)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3973)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3909)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2527)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2680)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2484)
at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1858)
at com.mysql.jdbc.PreparedStatement.executeUpdateInternal(PreparedStatement.java:2079)
at com.mysql.jdbc.PreparedStatement.executeUpdateInternal(PreparedStatement.java:2013)
at com.mysql.jdbc.PreparedStatement.executeLargeUpdate(PreparedStatement.java:5104)
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:1998)
at changeskin.hikari.pool.ProxyPreparedStatement.executeUpdate(ProxyPreparedStatement.java:61)
at changeskin.hikari.pool.HikariProxyPreparedStatement.executeUpdate(HikariProxyPreparedStatement.java)
at com.github.games647.changeskin.core.SkinStorage.save(SkinStorage.java:183)
at com.github.games647.changeskin.bungee.listener.AbstractSkinListener.lambda$save$1(AbstractSkinListener.java:46)
at net.md_5.bungee.scheduler.BungeeTask.run(BungeeTask.java:63)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
12:39:54 [FINE] [ChangeSkin] Applying skin for _Kuberq

#2

12:42:43 [SEVERE] [ChangeSkin] Failed to save preferences
com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Duplicate entry 'd77142539f7632bc9598e3a72f587d61' for key 'UUID'
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
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.Util.getInstance(Util.java:408)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:936)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3973)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3909)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2527)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2680)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2484)
at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1858)
at com.mysql.jdbc.PreparedStatement.executeUpdateInternal(PreparedStatement.java:2079)
at com.mysql.jdbc.PreparedStatement.executeUpdateInternal(PreparedStatement.java:2013)
at com.mysql.jdbc.PreparedStatement.executeLargeUpdate(PreparedStatement.java:5104)
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:1998)
at changeskin.hikari.pool.ProxyPreparedStatement.executeUpdate(ProxyPreparedStatement.java:61)
at changeskin.hikari.pool.HikariProxyPreparedStatement.executeUpdate(HikariProxyPreparedStatement.java)
at com.github.games647.changeskin.core.SkinStorage.save(SkinStorage.java:183)
at com.github.games647.changeskin.bungee.listener.AbstractSkinListener.lambda$save$1(AbstractSkinListener.java:46)
at net.md_5.bungee.scheduler.BungeeTask.run(BungeeTask.java:63)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)

Bungeecord: bungeecord build #1310

Please follow the issue report template.

This includes for example the plugin version. You can see it here:

https://raw.githubusercontent.com/games647/ChangeSkin/master/.github/ISSUE_TEMPLATE.md