I’ve recently often had issues while trying to import from Files, from SMB share. After some troubleshooting, it turned out Files app would crash while trying to open any files from that SMB share, listing directories was working. This is not apparent from within Panels because the import window stays open and nothing happens.
Removing and adding the SMB share within the Files app solved this issue for me.
Posting this to save time and nerves for anyone else that might encounter this issue.