Yes, it worked. I completely uninstalled Steam from my PC and performed a fresh installation. Unfortunately, this also removed all of my installed Steam games, but I didn’t mind since I could simply download them again afterward.
After reinstalling Steam and installing inZOI again, the issue was completely resolved.
@ryohere Didn’t work for me ! I don’t know !
I uninstalled and reinstalled Steam, but the game InZOI still won’t launch; it keeps showing an error.
When you uninstall steam, does it remove everything including all your others game files?
@ryohere I only uninstalled inZOI. I also downloaded the latest Steam installer from the official website, reinstalled Steam, and then reinstalled inZOI, but the issue is still there. Do I need to uninstall my other Steam games as well, or should I back them up to another drive before doing a complete Steam reinstall?
I performed a complete reinstallation of Steam. This removed all of my Steam files, including every installed Steam game. After that, I downloaded the latest Steam installer from the official website, installed Steam again, signed back into my account, and then reinstalled inZOI.
These were the exact steps I followed.
Oh ! It’s works after refresh all the games in hardware or SSD and reinstall all like @ryohere said !
Congrats! hopefully this will help the others as well!
Maybe we can mark it as solution for other people to see @ProKenDy 
. Glad a way has finally been found
Thanks @all in topic ! After 3 months we have found solution !
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If the solution is uninstall our steam and all the games, i rather just abandon inzoi as i got more than 2TB of installed games, some full with mods, also i do not want to reinstall them as steam will force me to install newer version of the game which got potential break most of the mods
but still, when got time i will try to make new user account in my windows to clean install steam client there.
Since there is still no official statement or direct hotfix from the development team regarding the authentication bug, i am hoping for a structural solution that doesn’t require completely deleting our Steam client and wiping our entire game libraries, as inzoi the only games with this kind problem in my steam library.
While we all understand that technical instability and game-breaking pipeline errors are risks we willingly accept when supporting and playing an Early Access title, having to nuke our entire platform ecosystem just to fix a single game’s DRM handshake feels incredibly steep. As a day-one player with over 100 hours invested, I truly hope the team can isolate this network ticket mismatch on their end so we can safely return to the game without risking the rest of our PC setups.
Good luck Inzoi and Devs!!!
@Yvri I’d recommend setting aside a little time to do a complete reinstall. Uninstall all your Steam games first, then uninstall Steam, and delete the entire steamapps folder. Make sure to back up your ~mods folder somewhere safe beforehand. Following these steps, as suggested by ryohere, is what finally got the game working for me. I hope it helps you too! 
I completely understand how @Yvri feels. I felt the same way at first. But because I really wanted to play the game again, I decided to start over from scratch. I backed up my ~mods folder and all of my custom textures for furniture and clothing, then uninstalled everything and reinstalled Steam and the game. It took me an entire evening, but in the end it was worth it because I was finally able to play again. I truly respect how you feel, and I understand your frustration. At the same time, I hope we can also give the developers a little understanding during this stage of Early Access, so they can focus on fixing bugs and improving the game for everyone in the future. 
I have one suggestion. If you have another drive with at least 2 TB of free space, you could try backing up your other Steam games there first. Then delete all the games from your current Steam library drive, perform a clean Steam reinstall, and once everything is working again, relink or move your other games back. It might save you from having to redownload your entire library. Just an idea—I hope it helps. 
I successfully access my inzoi again without touching or deleting my other games and inzoi itself, by simply install second steam client 
.
here the tutorial:
Create a New Folder: Create a completely new folder anywhere except your C: Drive (for example: G:\SteamTest).
SteamSetup.exe from the Steam website.G:\SteamTest).Once installed, go into G:\SteamTest.
Right-click steam.exe> Show more options > Create shortcut.
Right-click the new shortcut > Properties.
In the Target box, add a space and -portable to the very end of the line. It should look like this:
"G:\SteamTest\steam.exe" -portable
Click Apply and OK.
@yvri Wow, that actually sounds like a convenient solution and saves me from having to reinstall the game. My only concern is whether the two versions might conflict with each other. It also seems possible to create another Steam Library folder in Settings → Storage and install inZOI in a different library instead.
tried the two latest fixes in the thread, these have not worked for me. i only started having this issue after i changed my graphics settings yesterday; it was running fine otherwise. hopefully, there’s some fix somewhere, or this bug can be rooted out in a future update.
Have you completely removed all your Steam games? After uninstalling them, make sure to delete the entire Steam Library folder as well. Uninstalling Steam doesn’t remove your library folders automatically, so they can still contain old files. Once everything is deleted, try installing Steam and the game again.
Wow things have turned around! You are helping the players 