Hello, after knowing your problem. Here you have to know that the NTFS file system can't be written on Mac.
And there may be some configuration problems using the Paragon NTFS driver for Mac according to many technological debates.
For that you said you don't want to reformat it, you'd better uninstall this NTFS driver and choose a more appropriate one like iBoysoft NTFS for Mac, which can work better for writing and reading the NTFS drive seamlessly on Mac.
Then you can also try these ways:
- Enable Ignore ownership on this volume.
- Check the free space of the external drive.
- Restart the Mac and reconnect the drive with the Mac.
To avoid data loss, you're suggested to utilize iBoysoft NTFS for Mac.