Error and Multiple Warnings in Java Edition Server

I have been trying to host a Minecraft server and that has been going pretty good, the server still runs but I am concerned about the errors that pop up when I first start the server. If this is the wrong place to be posting it, I am sorry and please tell me the correct site to ask this question. 

I have attached the server log. 

 

Note: I am playing on 20w17a but it does not let me select that for affected versions.