Oculus Go recently updated it's default browser earlier this week. Now when entering "VR immersion" you have to click allow to give the website permission to do so.
It's possible Oculus may be preventing you from entering immersion mode because of this setting.
I'm not sure if you can give that website permission in Oculus settings.
Maybe try using the default Oculus browser first to see if it works. You may have to click allow.
After allowing, try Google to see if it works.
I hope this helps!
