Online mode error in joining own private server in Minecraft

We set up a private server and added the student’s Minecraft username. We are able to connect to Tynker server from multiplayer. But, when we type “/join”, we get “ExceptionConnecting:QuietException: Server is online mode!”. What do we do?

We had an issue with the new recent server upgrades related to Minecraft 1.16.1. These should be resolved now. If you are still seeing this issue, please reach out to support@tynker.com for help.

We are having the same issue. I have emailed support but I am curious what you did to resolve the error?
Thanks

Apologies - some users were still having this issue. We had to make more updates to our servers. Are you still seeing this issue now?