If you're reading this, something went wrong. Don't worry though, as this is the most thorough guide to help you!
No idea where you got that system. But we clearly do NOT support it.
Please check that you have downloaded the right version of Impostor, as we mantain two CPU architectures (x64 and ARM).
Unless you are running Impostor on a SBC (Single-Board Computer), like the Raspberry Pi, you most likely want to use the x64 version.
This is an error related to Linux file permissions.
Some files do not hold their executable bit (the permission that allows them to run) during a download.
You can solve this by doing: chmod +x Impostor.Server
You are using an older version of Impostor. The game does not really check who is outdated and blames it on the user.
Make sure you got the latest working version of Impostor (probably in AppVeyor, not Github).
Please double-check that you have followed the Server Configuration correctly.
NOTE: Your public ip does not start with 127 nor 192
Also check if the port Impostor (ListenPort) is listening on is correctly port-forwarded for UDP (or TCP/UDP).
Please check that you only have working plugins in the plugins folder.
This error can be caused by non-plugin files or plugins that are not working correctly.