Please ask Melco about the details of their file share. Roon does not have an own SMB implementation, it uses the one from the OS it runs on (QTS in your case). Settings you’ve made in QTS, or unchanged defaults, may prevent the successful connection. You can also try and mount the share directly in QTS, then you just point Roon at the local mount point.
Additionally: How did you install Roon Server on your NAS? Using the package or in Docker?
Then additionally the Docker instance might lack the right to mount (remote) filesystems. Please note that there is no official support for running Roon Server in Docker. You can use the thread below to help you with that. The information regarding Docker applies to other systems running Docker too:
Diagnostics don’t yet show a library location associated with the drive you’ve mentioned above. Have you tried the instructions that @BlackJack has shared in the post above?
We’re eager to assist from here if you’re still having issues, but this thread will automatically close in a few days without any further response from the OP.