Bad Version, server rejected connection [FIX]
First of all. DO NOT use the DayZSALauncher. Use the vanilla DayZ Launcher found within Steam.
Make sure you only have 5 mods the server uses which can be found here, any mods from other servers must be unloaded. The mods must also be in a specific order as shown below.
Go to your Dayz launcher and right click the 5 mods and repair each of them.
Go into steam library -> right click dayz -> prop