Getting a nullpointer exception when trying to submit an exercise

[VingGit]

in Intellij, clicking the send button on the course: https://ohjelmointi-20.mooc.fi/ gives this error.

and here's the full stacktrace:

java.lang.NullPointerException
at fi.helsinki.cs.tmc.intellij.services.exercises.ExerciseUploadingService.startUploadExercise(ExerciseUploadingService.java:55)
at fi.helsinki.cs.tmc.intellij.actions.buttonactions.UploadExerciseAction.callExerciseUploadService(UploadExerciseAction.java:63)
at fi.helsinki.cs.tmc.intellij.actions.buttonactions.UploadExerciseAction.uploadExercise(UploadExerciseAction.java:56)
at fi.helsinki.cs.tmc.intellij.actions.buttonactions.UploadExerciseAction.actionPerformed(UploadExerciseAction.java:39)
at com.intellij.openapi.actionSystem.impl.ActionButton.actionPerformed(ActionButton.java:172)
at com.intellij.openapi.actionSystem.impl.ActionButton.lambda$performAction$0(ActionButton.java:151)
at com.intellij.openapi.actionSystem.ex.ActionUtil.performDumbAwareWithCallbacks(ActionUtil.java:265)
at com.intellij.openapi.actionSystem.impl.ActionButton.performAction(ActionButton.java:151)
at com.intellij.openapi.actionSystem.impl.ActionButton.processMouseEvent(ActionButton.java:433)
at java.desktop/java.awt.Component.processEvent(Component.java:6419)
at java.desktop/java.awt.Container.processEvent(Container.java:2263)
at java.desktop/java.awt.Component.dispatchEventImpl(Component.java:5029)
at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2321)
at java.desktop/java.awt.Component.dispatchEvent(Component.java:4861)
at java.desktop/java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4918)
at java.desktop/java.awt.LightweightDispatcher.processMouseEvent(Container.java:4547)
at java.desktop/java.awt.LightweightDispatcher.dispatchEvent(Container.java:4488)
at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2307)
at java.desktop/java.awt.Window.dispatchEventImpl(Window.java:2790)
at java.desktop/java.awt.Component.dispatchEvent(Component.java:4861)
at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:778)
at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:727)
at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:721)
at java.base/java.security.AccessController.doPrivileged(Native Method)
at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:85)
at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:95)
at java.desktop/java.awt.EventQueue$5.run(EventQueue.java:751)
at java.desktop/java.awt.EventQueue$5.run(EventQueue.java:749)
at java.base/java.security.AccessController.doPrivileged(Native Method)
at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:85)
at java.desktop/java.awt.EventQueue.dispatchEvent(EventQueue.java:748)
at com.intellij.ide.IdeEventQueue.defaultDispatchEvent(IdeEventQueue.java:891)
at com.intellij.ide.IdeEventQueue.dispatchMouseEvent(IdeEventQueue.java:820)
at com.intellij.ide.IdeEventQueue._dispatchEvent(IdeEventQueue.java:757)
at com.intellij.ide.IdeEventQueue.lambda$dispatchEvent$6(IdeEventQueue.java:447)
at com.intellij.openapi.progress.impl.CoreProgressManager.computePrioritized(CoreProgressManager.java:818)
at com.intellij.ide.IdeEventQueue.lambda$dispatchEvent$7(IdeEventQueue.java:446)
at com.intellij.openapi.application.impl.ApplicationImpl.runIntendedWriteActionOnCurrentThread(ApplicationImpl.java:805)
at com.intellij.ide.IdeEventQueue.dispatchEvent(IdeEventQueue.java:498)
at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:203)
at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:124)
at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:113)
at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:109)
at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.desktop/java.awt.EventDispatchThread.run(EventDispatchThread.java:90)