Floating and/or connection bug.

In version 1.16.5, there is a problem joining my own server. When I join when no other people are on it loads the chunk I'm in, but then when I go to open a chest or break a block it doesn't work. I'm unable to open the chests, or when I break a block the block doesn't drop. At first in the server logs it said that I was kicked for floating too long, but now it says it's a connection problem. My connection is fine. Not to mention after about a minute of not being able to do anything and nothing loading it kicks me out of the server.