2020-05-09 12:19:26.516+0000 [id=38]    WARNING jenkins.model.Jenkins$5#runTask: Loading global config failed perhaps due to plugin dependency issues
java.lang.LinkageError: loader constraint violation: when resolving method "org.slf4j.impl.StaticLoggerBinder.getLoggerFactory()Lorg/slf4j/ILoggerFactory;" the class loader (instance of hudson/PluginFirstClassLoader) of the current class, org/slf4j/LoggerFactory, and the class loader (instance of org/eclipse/jetty/webapp/WebAppClassLoader) for the method's defining class, org/slf4j/impl/StaticLoggerBinder, have different Class objects for the type org/slf4j/ILoggerFactory used in the signature
        at org.slf4j.LoggerFactory.getILoggerFactory(LoggerFactory.java:418)
        at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:357)
        at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:383)
        at hudson.plugins.ec2.CloudHelper.<clinit>(CloudHelper.java:24)
        at hudson.plugins.ec2.EC2Computer.getState(EC2Computer.java:139)
        at hudson.plugins.ec2.EC2RetentionStrategy.start(EC2RetentionStrategy.java:241)
        at hudson.plugins.ec2.EC2RetentionStrategy.start(EC2RetentionStrategy.java:52)
        at hudson.model.AbstractCIBase.updateComputer(AbstractCIBase.java:162)
        at hudson.model.AbstractCIBase.access$000(AbstractCIBase.java:44)
        at hudson.model.AbstractCIBase$2.run(AbstractCIBase.java:224)
        at hudson.model.Queue._withLock(Queue.java:1398)
        at hudson.model.Queue.withLock(Queue.java:1275)
        at hudson.model.AbstractCIBase.updateComputerList(AbstractCIBase.java:207)
        at jenkins.model.Jenkins.updateComputerList(Jenkins.java:1635)
        at jenkins.model.Nodes$9.run(Nodes.java:351)
        at hudson.model.Queue._withLock(Queue.java:1398)
        at hudson.model.Queue.withLock(Queue.java:1275)
        at jenkins.model.Nodes.load(Nodes.java:346)
        at jenkins.model.Jenkins$13.run(Jenkins.java:3254)
        at org.jvnet.hudson.reactor.TaskGraphBuilder$TaskImpl.run(TaskGraphBuilder.java:169)
        at org.jvnet.hudson.reactor.Reactor.runTask(Reactor.java:296)
        at jenkins.model.Jenkins$5.runTask(Jenkins.java:1131)
        at org.jvnet.hudson.reactor.Reactor$2.run(Reactor.java:214)
        at org.jvnet.hudson.reactor.Reactor$Node.run(Reactor.java:117)
        at jenkins.security.ImpersonatingExecutorService$1.run(ImpersonatingExecutorService.java:59)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
        at java.lang.Thread.run(Thread.java:748)


...




2020-05-09 12:19:27.321+0000 [id=46]    SEVERE  hudson.triggers.SafeTimerTask#run: Timer task hudson.slaves.ComputerRetentionWork@5988e277 failed
java.lang.NoClassDefFoundError: Could not initialize class hudson.plugins.ec2.CloudHelper
        at hudson.plugins.ec2.EC2Computer.getState(EC2Computer.java:139)
        at hudson.plugins.ec2.EC2RetentionStrategy.internalCheck(EC2RetentionStrategy.java:146)
        at hudson.plugins.ec2.EC2RetentionStrategy.check(EC2RetentionStrategy.java:107)
        at hudson.plugins.ec2.EC2RetentionStrategy.check(EC2RetentionStrategy.java:52)
        at hudson.slaves.ComputerRetentionWork$1.run(ComputerRetentionWork.java:70)
        at hudson.model.Queue._withLock(Queue.java:1398)
        at hudson.model.Queue.withLock(Queue.java:1275)
        at hudson.slaves.ComputerRetentionWork.doRun(ComputerRetentionWork.java:61)
        at hudson.triggers.SafeTimerTask.run(SafeTimerTask.java:91)
        at jenkins.security.ImpersonatingScheduledExecutorService$1.run(ImpersonatingScheduledExecutorService.java:58)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
        at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308)
        at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180)
        at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294)
        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)