Hey everyone. I was getting this error when I was running Ubuntu 1.16.201 bedrock server on a Ubuntu 20.04. I installed Ubuntu 18.04 and tried the server software and it works! Looks like it's just affecting 20.04. Hope this helps someone!
Any updates on this? I'm trying to setup an Ubuntu bedrock server for the first time and I am getting the exact same results report above. I have tried on a world I created with no add ons (100% vanilla) and I have tried with a brand new world with the same results and same errors (not attached because they are the same as screen shot above).
Windows 10 OS: I had this issue, but only with one out of three users on the server. We destroyed the portal in both the overworld and in the nether and that fixed the issue.
I think I was mistaken in my previous comment re: the version of Ubuntu. I think the issue was the file location on the computer (virtual machine in my case). For some reason, the server only works for me if the server.properties and whitelist.json files are one folder up from the server software folder. This is my first foray into the Linux OS, so I am not sure if this is a settings thing or ubiquitous across all instances of the software. Anyway, hope this helps!