This article lists common issues and problems people have with playing Zandronum, and solutions and workarounds for them. For help with creating servers, see Game Servers Troubleshooting.
This means your Zandronum client is of a different version to the server you are attempting to join. Most servers are running the latest stable release, which can be downloaded from Zandronum's download page. Some servers may be using beta/testing versions which can be downloaded by your server browser and handled separately without overwriting your stable version, see Setting up testing versions.
If you've downloaded the latest version of Zandronum, but your client still seems to be using the older version, it likely your server browser is pointing to the wrong zandronum.exe. With Zandronum 3.1, the Windows installer was changed to install Zandronum in C:\Users\username\AppData\Local\Zandronum by default, where it was C:\Program Files (x86)\Zandronum in prior versions. Check your server browser's settings to make sure it's correct:
- Doomseeker: from the main window, open the Options menu and click Configure. Then, navigate to Games -> Zandronum. Ensure "Path to game executable" is set correctly.
- Doom Explorer: Open the Options from the top menu. Then select Programs. Ensure Zandronum's path is set correctly, and use the Change button to fix it if necessary.
Level authentication failed
This means that the level data on your computer is different to the level data on the server.
Firstly, ensure you are not using Freedoom, as Freedoom's maps are entirely different to and incompatible with vanilla maps. Most servers require a registered version of the game IWAD to play. If you are using the actual game's IWAD, ensure it is the correct version. You can use a tool such as Omniscient to patch your IWAD files to the correct version. Pretty much all Doom servers use The Ultimate Doom 1.9, and all Doom 2 servers use version 1.9.
If the issue still occurs, it is likely one of your mod files is of an invalid version or even corrupt: see the Protected lump authentication failed section,
Protected lump authentication failed
This occurs when the files loaded by your client do not match the files loaded by the server. The usual solution to this problem is simple: delete the mismatched files, and re-download them. When downloading files using Wadseeker or GetWAD, pay close attention to which website the files are downloaded from - if a specific site keeps serving up invalid files, you might want to remove it from your server browser's settings.
Additionally, ensure there are no gameplay mods in the skins or announcer folders within Zandronum's configuration directory - as their names suggest, these folders are for skins and announcers only, and you should never put any gameplay mods in there.
- FAQ (needs updating!)