This only occurs for me on a multiplayer server(19w09a) if the render distance in the client is set below the view distance configured in the server.properties file. Then the server wont load any more chunks outside the already loaded world.
I dont think, this is a duplication of MC-139717, because the bug ONLY occurs on a multiplayer server and not in singleplayer. Also the issue is depending on the diffrent settings of server and client. Nothing of this is described in MC-139717
This only occurs for me on a multiplayer server(19w09a) if the render distance in the client is set below the view distance configured in the server.properties file. Then the server wont load any more chunks outside the already loaded world.