unexpected exception during matlab activation

I keep getting this error during activation:

There was an unexpected exception:

null

See the log file (C:\Users\...) for more details.

THe following is the content of the log file:

(Sep 26, 2019 22:07:02)THE ACTIVATOR IS STARTING UP.

(Sep 26, 2019 22:09:46)org.apache.axis2.AxisFault: java.lang.RuntimeException: java.lang.NoClassDefFoundError: Could not initialize class com.mathworks.internal.accesslogin.sva.ProofLocationListFactory

java.lang.RuntimeException: java.lang.NoClassDefFoundError: Could not initialize class com.mathworks.internal.accesslogin.sva.ProofLocationListFactory

org.apache.axis2.util.Utils.getInboundFaultFromMessageContext(Utils.java:446)

org.apache.axis2.description.OutInAxisOperationClient.handleResponse(OutInAxisOperation.java:371)

org.apache.axis2.description.OutInAxisOperationClient.send(OutInAxisOperation.java:417)

org.apache.axis2.description.OutInAxisOperationClient.executeImpl(OutInAxisOperation.java:229)

org.apache.axis2.client.OperationClient.execute(OperationClient.java:165)

com.mathworks.mlwebservices.svact.StudentVersionActivationServiceStub.getLocations(StudentVersionActivationServiceStub.java:987)

com.mathworks.activation.StudentActivationServiceWrapper$LocationsTask.run(StudentActivationServiceWrapper.java:494)

java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)

java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)

java.util.concurrent.FutureTask.run(Unknown Source)

java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)

java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)

java.lang.Thread.run(Unknown Source)

(Sep 26, 2019 22:10:11)The application could not connect to MathWorks. Please make sure your internet connection is available and that all software and hardware firewalls have been disabled before retrying your request.

(Sep 26, 2019 22:10:11)java.lang.NullPointerException

com.mathworks.activation.AccessLoginInfoPanel$NextAction.getLocations(AccessLoginInfoPanel.java:531)

com.mathworks.activation.AccessLoginInfoPanel$NextAction.doNextButton(AccessLoginInfoPanel.java:473)

com.mathworks.activation.AccessLoginInfoPanel$NextAction.actionPerformed(AccessLoginInfoPanel.java:420)

javax.swing.AbstractButton.fireActionPerformed(Unknown Source)

javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)

javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)

javax.swing.DefaultButtonModel.setPressed(Unknown Source)

javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)

java.awt.Component.processMouseEvent(Unknown Source)

javax.swing.JComponent.processMouseEvent(Unknown Source)

java.awt.Component.processEvent(Unknown Source)

java.awt.Container.processEvent(Unknown Source)

java.awt.Component.dispatchEventImpl(Unknown Source)

java.awt.Container.dispatchEventImpl(Unknown Source)

java.awt.Component.dispatchEvent(Unknown Source)

java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)

java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)

java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)

java.awt.Container.dispatchEventImpl(Unknown Source)

java.awt.Window.dispatchEventImpl(Unknown Source)

java.awt.Component.dispatchEvent(Unknown Source)

java.awt.EventQueue.dispatchEvent(Unknown Source)

java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)

java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)

java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)

java.awt.EventDispatchThread.pumpEvents(Unknown Source)

java.awt.EventDispatchThread.pumpEvents(Unknown Source)

java.awt.EventDispatchThread.run(Unknown Source)