not being able to go at full speed by using the elytra and the fire works i see that it says that i am going to fast but im not using hacks

i im running a server on my pc for the first time and i wanted to test the limit and i put on the elytra and the fireworks as its the fastest way to get around and i get to a fast speed and it bonces me back and i look at the command prompt and it says [18:16:10] [Server thread/WARN]: winwinner moved too quickly! -7.49681863812873,-3.930347666025625,-16.94141411736672 i tryed it more and it and says the same thing