Internal Server Error when attempting to Import Slack


Whenever I attempt to start the import process (specifically, clicking on the Slack or Slack Users button in the Import menu), an internal server error happens, which is logged as:

I20191109-17:45:49.431(0) Exception while invoking method ‘getSelectionData’ TypeError: Cannot read property ‘map’ of undefined at SlackImporter.getSelection (app/importer-slack/server/importer.js:556:43) at MethodInvocation.getSelectionData (app/importer/server/methods/getSelectionData.js:30:30) at MethodInvocation.methodsMap.(anonymous function) (app/lib/server/lib/debug.js:62:34) at maybeAuditArgumentChecks (packages/ddp-server/livedata_server.js:1771:12) at DDP._CurrentMethodInvocation.withValue (packages/ddp-server/livedata_server.js:719:19) at Meteor.EnvironmentVariable.EVp.withValue (packages/meteor.js:1234:12) at DDPServer._CurrentWriteFence.withValue (packages/ddp-server/livedata_server.js:717:46) at Meteor.EnvironmentVariable.EVp.withValue (packages/meteor.js:1234:12) at Promise (packages/ddp-server/livedata_server.js:715:46) at new Promise () at Session.method (packages/ddp-server/livedata_server.js:689:23) at packages/ddp-server/livedata_server.js:559:43

Server Setup Information

  • Version of Rocket.Chat Server: 2.1.1
  • Operating System: Ubuntu 18.04.3 LTS
  • Deployment Method: snap
  • Number of Running Instances: 1
  • Proxy: nginx

Any additional Information

This came about after I first attempted to Import. I was able to navigate to /admin/import/prepare/slack and chose a zip file, but I did not initiate the actual import. I have not be able to return to this page since.