So I have been working on my spigot server, and suddenly, I accidentally break a command block. I try to place it back, but when I try to, the block flashes in front of my screen then disappears. I try placing other blocks in other places, but those do the same thing. I am opped. I need help! EDIT: I get these warnings on restart of server. *** Error, this build is outdated *** java.lang.NoSuchFieldException: packetListener I get more but those are the only two I am worried about, especially the second one.