Seems quite a few people complaining in the comments on the GOTD download page that it's not installing or activating...
We pretty much all have a handle by now on various security apps blocking the GOTD install, & if/when that happens, disabling the security software or restarting in Safe Mode. Personally I'm a bit surprised that it's still a problem, since even Kaspersky doesn't seem to mind anymore, at least the free version in one of my VMs.
Problems activating the software may be a bit newer. I *suspect*, particularly with Wonderfox software, that security software is blocking access to the user files [C:\ Users\ [UserName]\] as a means of Ransomware protection. The complaints of course don't provide any info, e.g. the brand/model of security software, so it's just a guess, but Wonderfox software is almost portable, with the only thing outside the program's folder being registration or activation info stored in a user folder. Since only some are having problems the keys are probably good, & there's really not much else that can go wrong.
That said, like other Wonderfox apps the DVD Converter works 'bout the same as others. With so many screens at 1080p or better, & so many phones without sd card slots, best is probably streaming, if you've got the data allowance. 2nd best is probably Blu-ray, re-encoded to a smaller file if storage is limited. 3rd is Blu-ray re-encoded & resized comparable to DVDs if storage is really tight &/or you've got a lower rez screen. 4th is DVD mpg2 video not re-encoded, & dead last in terms of quality is DVD mpg2 video re-encoded to something like AVC. That's because the average retail video DVD has its video quality reduced to the point that it can't withstand the data loss of re-encoding. And yeah, that's done on purpose so people don't re-encode DVDs -- they can get away with it nowadays because frankly [& no offense intended] those watching DVDs in the 1st place aren't overly concerned about quality or they'd be streaming 1080p or watching Blu-ray.