Blank CD-R Keeps Ejecting (Other Types Are Ok)

Hi. On Boot Camp Window 10, I was burning a .cdi image to a blank CD-R Verbatim (written on the disk are: 52x, 700MB & 80 minutes) using imgBurn app but it had an error something about a track and a mode. It asked something about close to which I clicked "no". It has burned 70MB into the disk and it's not unwritable or closed (90% of the disk wasted in short).

Now, the late-2009 iMac keeps ejecting blank/new CD-Rs of any brand (Sony, Verbatim) but other types are ok and are being mounted: DVD-R, CD-RW. I even got to burn an image onto the CD-RW with contents full. This happens on both OS X El Capitan and Windows 10 64-bit

Strangely when it mounts a CD-R that's full normally without problems.

How can this be fixed? And what happend to it that it only ejects blank CD-R disks (newly bought even)

Thank you in advance.

God bless, Rev. 21:4