Which command did you run and what did it say when you run it?
Looks like multiple users are reporting that this plugin is broken https://dev.bukkit.org/projects/essentialspro
Did you make any changes to the config file of this plugin? I will suggest that you rename the EssentialsPro folder to EssentialsPro_test while...
Please post your essentials config and your permissions file.
Please send the full console log. And how much RAM do you have allocated to the server?
Please post your server's startup console log.
Try the commands below. /region flag <region> use allow /region flag <region> interact allow /region flag <region> chest-access allow
Try removing the EssentialsXAntiBuild plugin.
Try running an MTR report to your server to see if you any packet drops. http://winmtr.net/
Is the paste bin you linked the broken permissions file?
You would need to install a permissions plugin, then give the other players permissions to use the kit commands.
I checked your file, but it looks like the Dev group does not have the essentials.fly perm. You would need to add it to that group for them to...
Can you give an example of a group you added a user to, and what commands do not work?
You could try NuVotfier: https://github.com/parallelblock/NuVotifier/releases/tag/v2.4.0 However 1.13.2 is still very new, so you may need to...
Separate names with a comma.