Why isnt TabCompletion working?

I am having a problem with typing in commands and it is really bugging me. I am currently running the latest version of Spigot as of April 3rd, 2019. The server is on 1.13.2 and I use Optifine on the client side.



The problem is when I try to tab complete a command or put in a username using the tab key, it does not work. The text would immediately turn red after typing it in giving no command suggestions at all. I do not really know when my problem started but it took me about two hours to notice after playing around with plugins. Note that I do have command suggestions turned on in my settings.



I use /time as an example. It should give me suggestions but it does not. I hopped onto a single player world to see if it was my problem and it wasn't the problem. The top picture is of my server and what the problem is and the bottom picture is a local single player world and what should be happening with the commands. I checked command blocks too, the same thing.





[Blocked Image: https://www.spigotmc.org/data/attachments/415/415445-8d0c16331f51c900fc261a9d2f8f40cc.jpg]

[Blocked Image: https://www.spigotmc.org/data/attachments/415/415450-673e5cd7c7857b83c5c707c0aebb7941.jpg]





I tried some things to see if I could fix it myself. I do not know if it is a problem with plugins or with another thing but I did take out all the plugins to check if that was the case and it was not. I had this problem on PaperMC but then switched to Spigot to see if that would work and it did not work either. I installed a plugin (CommandAPI) that I thought would supposedly fix the problem but it did not. I do have about 130 plugins running but I could be wrong about it not being a plugin. I checked opped players and unopped players and unfortunately, the same thing occurred. I tried messing with permissions too, no luck there.



Has anybody else run into this problem before? Does anybody have any clue what the root cause of this is and how to fix it? I am fairly new in running servers but this server is a small server for me and my friends to play on. Thank you in advance.



EDIT: I forgot to mention that the commands do work as they are supposed to so it's not the biggest issue.