Alright, let’s get your issue sorted!
When you change the online-mode to false but it reverts back to true, it’s often because AMP’s settings are overwriting the server.properties file.
Here’s the play-by-play:
- Open AMP’s web interface.
- Search “online-mode” in the Search box at the top right.
- Set “online-mode” to false in AMP’s settings and save.
Once you’ve done that, restart your Minecraft instance and see if the setting sticks.
Give this a go and let me know if it’s still being stubborn!