Port 1900 is used for SSDP/DLNA connections. If Media Server is running in MC, then those messages would be some DLNA Client trying to connect, or MC looking for DLNA Clients, or something like that. MC doesn't need port 1900 open for Auto Import to work.
You shouldn't have to delete the library and start over, ever. In fact, doing that just hides the problem and it will never get fixed.
In the Standard View Navigation Pane on the left, can you open the "Drives & Devices > Explorer > etc." and navigate to the location where your new HDTracks are stored?
If you can find the files there, check the [Media Type] tag is set to "Audio".
If you double-click on one of the files in there, does it play?
Can you navigate to "Audio > Files > etc." and drill down to the same location where your new HDTracks are stored?
If so your files have been imported, and they must just have some tags set so you don't see them in the Views you are using. Of course, to see them in the above, they must be correctly tagged as [Media Type]=Audio.
If you can see then in the MC "Drives & Devices > Explorer > etc.", but can't see them under "Audio > Files > etc." even though they are tagged correctly as Audio, do you have "Ignore previously removed from library" ticked in the Auto Import settings?
If so, unticked that setting and run Auto Import again.
Let us know how you go.
Paragon shouldn't be the issue. But Paragon may not be sharing File Events with the MAC, which MC uses to almost immediately import any new files. (At least MC does on Windows, and I think it is the same for the MAC version.) Auto Import should still find the files though, as it does run regularly to check for new files. Also, a manual run of Auto Import should find the files.