I bought just Nuendo 14, so I will be able to upgrade to #15, on the Cubase Pro 14 crossover deal. But when typing in the redeem number in the Steinberg Download Assistant, it says that I don’t have a license for Cubase Pro 14… which of course is incorrect ;-/
Is this something many others here have been experiencing? I registered a ticket, but have not received a response yet.
Do you own a Cubase 15 license? The latest licensed version is the one that will define you as a Cubase 14 or Cubase 15 user. Cubase 15 users are not eligible to use this crossgrade although they own the right to use Cubase 14. It doesn’t matter if you bought Cubase 14 separatly at one point.
If this is the case the only viable option is to ask for a refund:
You shouldn’t need a license to download Nuendo 14, once downloaded try using your new license in the Steinberg Activation Manager. I just downloaded Cubase 15 without any license just so I could check it out before Nuendo 15 is released. No issue’s.
@Wheels I think you misread the OP’s post.
Entering the Download Access Code produces an error message which reads that the OP doesn’t own the required Cubase 14 license for that specific crossgrade.
You confused it with trial versions which don’t require DACs.
Yes, I have licenses for Cubase 11, 12, 13, 14, and 15. I still have Cubase Pro 14 installed on the computer, although I work more in Cubase Pro 15. What about if I should deactivate Cubase Pro 15 in the Steinberg Activation Manager? Would this help the Nuendo 14 download?
So you have Cubase 15 as the latest license. I guess this is an update from a previous Cubase 14 license, correct?
In that case you can not crossgrade to Nuendo 14, because the Cubase 14 license has already been consumed by the update to Cubase 15. You can still run all previous releases back to Cubase 12 (everything else before required the eLicenser), but for updates and crossgrades only the latest license counts.
@Thor.HOG had a long discussion about this in a different thread already.
To add to the excellent advice already shared, you can view your actual product licenses for your account in the Products section of your MySteinberg account.
Again, you may be confusing the fact that C14 “runs” on your system with having a C14 license, rather than the C15 license granting you access to previous versions supported by Steinberg Licensing. If you only see “Cubase 15 Pro” in that list (excluding trial listing) then that’s the problem.
However - and importantly in your case - there seems to be an addition rub here - SB has indicated that Cubase 15 owners CANNOT purchase N14 crossgrades yet: only Cubase 14 and below can. This is evidenced by the fact that C15 isn’t listed in any of the “qualifying products” requirements. I understand the explanation to be that since N14 can’t fully support C15 project files, that they won’t offer it to you even though it’s a completely different product. I personally think that’s a bit of a “user coddling overreach” but they didn’t ask for my opinion 
I think they should have at least put a disclaimer saying “C15 users have to wait for their own sale because we don’t think they’re smart enough to know the difference between C15 and N14.” 
But I digress. Word on the street is that when N14 N15 is released that C15 users will be able to purchase it for 20% off, or whatever it turns out to be.
If you only have an actual C15 license listed, you’ll need to ask support for a refund.
EDIT: “When N15 is released…”
haha …..if anyone’s still waiting for Nuendo 14 to release for the first time, someone’s got some ‘splainin’ to do