If you ever get kicked from a server due to "Authentication Failure", then there could be an issue with your IWAD file. This can be that you are possibly using an unpatched/outdated IWAD file.

So lets check to see if your IWAD is up to date. Before we start, please download the MD5 Hash program. This is a stand alone program, so you do not have to install it.

When you open your IWAD files with the MD5 Hash application, be sure that it matches with the information below: