Error message is reported in Resilio Connect v 3.4.0 and newer.
Resilio Agent scans the folder right after the job is created and then periodically at the given interval. During this scan the Agent checks files attributes (timestamps, size) and records this information in the database. The error message means that the Agent was not able to read the file or the folder information. The reason for it may be different and it's reported in the message, this is a system's message.
To fix the error, resolve the reason and launch the scan again.
Error code SE_FS_CANT_LIST_FOLDER.