PDF previews are not shown in imported messages (Slack)

Dear All,

We are planning migration from Slack to self-hosted RocketChat server. Now we are in testing phase.
I found that for messages with attached pdf files imported from Slack there is no pdf preview shown. Fresh messages sent within RC do show small pdf preview. While it is not a big deal I would prefer to fix it and have pdf preview images also for imported Slack messages.

For png/jpeg/mp4 files in imported Slack messages preview is shown!
I checked and all corresponding files are downloaded and saved on local filesystem. We use “FileSystem” storage for our server. All files, including pdfs, are downloadable from our RC server.

Perhaps some tags are not added to attachments during import? I guess we can edit imported messages in our DB.

Thank you in advance!



Server Setup Information

  • Version of Rocket.Chat Server: 3.9.1
  • Operating System: CentOS 8
  • Deployment Method: tar
  • Number of Running Instances: 1
  • NodeJS Version: 12.18.4
  • MongoDB Version: 4.0.21
  • Proxy: nginx
  • Firewalls involved: yes