Minecraft command is not working? - 1

Hi, I have the problem that if I enter a command on my mc-host24 server that you would not otherwise be able to enter, it will not work. This also applies to a command given by the server, such as / plugins or / pl. Since I put the server on the 1.13. Switched, it is no more, before on the 1.8 everything went. Furthermore, I can't install any plugins, even if everything works fine with the installation, divorced simply nothing more if I add a plugin and also extended by the plugin Commands are not synonymous. I'm pretty sure that I do everything the same way as before, I already know how to install plugins… Has something sometime ago something at MC host or in general something done there, that you load plugins differently on the server?

Above all, stop / pl is no more, as if I had no server.

If / pl did not work I would have said that spigot / bukkit was not loaded… Check if you have a) the right version, b) if it is loaded

Look sometimes synonymous if you find any logs / crash report and after the respective error code…

That does not sound good. If I had a PC error, then I always restarted mine, try that and then tell me if that helps.