Vehicle registered before 2015
The security codes have only existed since early 2015. If your vehicle was registered before then and never re-registered since, they may be missing.
The check costs nothing and you reveal nothing during it.
How to tell
Look at the back of your Fahrzeugschein. If there is a green sticker on it, there is a code underneath. If the vehicle has been re-registered since 2015, the seals on both plates carry a code too, and online deregistration is possible.
If there is no green sticker and the vehicle has not been re-registered since 2015, there are most likely no codes. In that case only the counter route remains.
If the codes are missing
Then neither we nor any other provider can deregister your vehicle online. That is not a question of the provider but of the law: without the codes, § 24 FZV requires identification of the applicant.
Check it with us for free. If it turns out not to work, you pay nothing and we send you the address of your registration office.