Either the server hasn't been updated with the latest version of a mod or you are having an issue with your mods on your local system.
To check if it's the server or yourself, ask a friend or check: https://jrnetwork.net/servers/list to see if anyone else is logged in.
If it's only you that can not login:
Steam may not have ran an update, check your client for updates that are waiting to be installed.
If nothing has come through to your client you could be in a queue to receive the mod update.
The best solution to get past this issue would be to re subscribe to the mods we use to make sure that everything is up to date. You can do that by going to: https://steamcommunity.com/sharedfiles/filedetails/?id=940316400 Click unsubscribe form all then click subscribe to all after a few seconds.
This should make steam check for updates.
The other issue you could be having is not having the Ragnarok, Center or Scorched Earth DLC not installed. Make sure the DLC is installed. If all fails you may have to delete all the mods in your mod file and resubscribe again so it downloads the latest mods we use.
You could also be having an issue with your steam installation.
Either delete the mod files found in ShooterGame/Content/Mods and then resubscribe to all our mods https://steamcommunity.com/sharedfiles/filedetails/?id=940316400
Run a steam verification on game files. (Right click on ARK, Click Properties, Local Files, Verify Integrity of Game Files)
Any more issues or if the above does not work please contact a member of staff via the help center: https://jrnetwork.net/help/help-center/
Edited by Jamie