[Samsung Galaxy S10 Themes, Apps, and Mods] WookieLance:
I read a few pages, will be honest did not ready every comment.

Main things I see are struggles with licence keys and compile, may have a look at the official repo again after the weekend and update both threads OP with compile method based on the repo script maybe I can find time to make the repo script a little easier to simply just download the master repo and run script in the extracted content and its done, but honestly it no amount of compile is going to get around the fact that the licence key has to be valid and it is only valid for 3 months and 6 installs under the same package name.

I can fix the problem with donations as I can use the donation to buy a developer commercial key which will not run into these issues and has no expire time and unlimited activations under the same package name but I am not going to sit here and honestly ask for donations when a little bit of brain churning can resolve the issue individually.

I sat here already and thought about making a new package with a commercial key just to end the fuss over the key issue and everyone scrambling around over what I thought at least were a mostly simple answer to why the pre-built package in the OP is not working anymore. I read plenty of good advice in last 10-15 pages many bring up the easy to compile script which is not the method I used but any method which compiles the repo is good enough, so bring your valid key if you can get one and whatever software/ hardware you want to use to compile the APK with and put the key into the right place and build and you will find no more problems until three months later when you need to renew the key online else it will deactivate! but you Samsung Knox Emails you prior to this and I re-activated the key on the OP APK however it will not fix it for the vast majority of you it will only fix it for the lucky five other people who installed it first before the Package name became invalid for further device installs as believe it or not the device ID is tracked by Knox and six installs is all you will get without the commercial key.

It has not stopped working for me but as I stated I installed it first so there is no reason it won't work so long as I continue to renew the key every three months, and it will keep working for the other five lucky folks too.

I felt the OP needed an update to explain why everyone was getting the error so I provided a few links and explanations for what was the best replies at the time, I can see that a fresh compile via the repo script is probably the better way to go about the problem and this will look into it.

I think I may have a couple of spare EDU keys I generated under different names for testing might still work so at least 12 of you will get it going without an issue if I do have said keys valid.

Thanks for all the feedback thus far, I just wanted to post about this tbh, and the OP was mainly just to bring this thing back from the dead as it intrigued me and with the S10 being my first Samsung device since a Note 1 and how attempting to Root my device, for now, would lock me out Knock and all its glory ADHell was a pretty solid choice to take the time to bring back from the dead at least for my uses.

As it did a couple of key things I wanted, one of which is disabled system apps without root likely because Knock as root access to the device so its a neat little trick if that is the case by using Knock do your root dirty work, I can see why Samsung banned ADHell and removed it from Samsung store and the Samsung dev who originally came up with the app was told not to continue to support it or share it, as I can see how it goes against a few internal security policies.

Needless to say if KNOX can perform root tasks I may look into it further and see if I cannot get some kind of Root tool working via KNOX and thus not bricking KNOX on the S10 by running TWRP and or Magisk but instead access root partitions via KNOX commands. If that is a viable option I will get pretty excited.

All we know for sure is Samsung really does not like ADHell being a known thing and used on their devices, as they are the ones who shut down the development of the initial work.

If you are lucky and have keys already then it might work for some time, maybe this will just be broken from here on out after the current batch of keys expire who knows. I have no idea if they are letting users who generated keys prior to their new partner thing get to keep their keys or not.

Another thing,

While the Key cannot be generated for S9-S10 devices

you should have also got a older device key this one does not expire

"Backwards compatible key"

I do have this activated in the APK in the OP so older KNOX devices should in theory still work with Adhell3.