Whether you are launching the game through or directly via Content Manager ?
When you see this error, it means a mismatch exists between your game files, your mod manager, and the server you are trying to join. Common Causes assetto corsa is obsolete v1.16.3 is required
Navigate to your Assetto Corsa root folder (usually SteamLibrary\steamapps\common\assettocorsa ). Locate a file named . Whether you are launching the game through or
Old versions of CSP may not be compatible with newer Steam updates. In Content Manager, go to > Custom Shaders Patch . your mod manager
Does this happen on or just one specific server/mod ? Is your game a legitimate Steam copy ?