Updated the mod in my pack from version 1.99 to 1.99.1 and immediately get an exit code crash. So I don't have any logs to give. However, knock the mod back down to version 1.99 and it works just fine.

Modpack is here: https://www.curseforge.com/minecraft/modpacks/mageknight-chronicles

So you can see a list of the present and active mods. But as mentioned it works fine when I use version 1.99, it is only in 1.99.1 that the Crash Occurs.

Check if you have Lionfish API installed as it is a required dependency for 1.99.1

I did have the Lionfish API installed however I do now want to point out updating to 1.99.2 there is no longer an Exit Code Crash so it seems to have been fixed as everything now seems to load fine.