My friend used to be able to play just fine, but now when he logs into my server the world doesn't render at all and he times out after a little while. It shows him as on the server and he can send chat messages until he times out. His computer has good specs and since everything worked up until a couple days ago, I'm not sure what's causing the issue. Any help would be appreciated.
Edit: forgot to mention this is a vanilla server on 1.14.4.