Things that can help you to figure out why it happens:
Make sure you have the latest stable Sponge version.
Make sure you have installed GWMLibrary.
Check your configs (including crates' configs) using this site
Check console for errors (exceptions) often they have yellow or red color. If they are related to this plugin, they must contain words "gwm_crates", "GWMCrates" or anything similar.
Execute /gwmcrates list command to check if your crates have been loaded successfully.
If you still can't figure out why it happens, welcome to our discord server
I created "BLOCK" crate, but I don't see it in-game, at specified location.
Plugin does not automatically place block at specified location, you must do it itself.
Plugin listens for clicks at specified location.
I created "BLOCK" crate, but it seems to be at wrong location.
Make sure to recheck location of your block.
For that press F3+H and check looking at parameter.
How levels system works?
Minimum value for level is 1.
Maximum level is unlimited (but high levels are really useless, because they have really low chance).
The higher level - the smaller chance to win drop with this level.
Each next level has twice smaller chance then the previous one.
Level 1 - 50% chance
Level 2 - 25% chance
Level 3 - 12.5% chance
Level 4 - 6.25% chance
Level 5 - 3.125% chance
Level 6 - 1.5625% chance.
Level 7 - 0.78125% chance.
Level 8 - 0.390625% chance.
And so on...
How fake levels work?
They work the same way as levels, but only for items that player will not get.
There drop with diamond block has high level (8), but low fake level (1), and dirt has low level (1), but high fake level (8). TBD