Incompatible FML Modded Server / Big Red X

Sometimes there is a big red X on the right of a server in the Multiplayer menu in Minecraft. This can happen for a few reasons. Here are common ways to troubleshoot this:

Try connecting anyway. Often this message can appear even when everything is installed properly. If this is the case, there's nothing to worry about and you can ignore the message and the big red X.
Verify that your modpack and your server are on the same version. See Update a Game on how to change your server's version.
If you have made any manual changes to your mods such as adding, removing or updating individual mods manually, undo those changes and see if that helps. Make sure you installed the mods to both client and server, if they are not client-only mods.
If all of the above fails, reinstall the server files and/or your local modpack. To reinstall your server files, you can follow the instructions in Update a Game and just "update" to the same version you are already on. You may also want to manually delete everything in the mods folder before doing this, just in case.

If you do continue to have issues please contact us anytime and we will answer you as soon as we can during business hours.