Can't change player data

I opened up an Origin Adventure mod pack server and at first it would not let me join, fixed that, but now I can't change player's data, can't op, white light, ban, heal, change game model, anything.

It did say error 451 but I can't find any information about what it means.

update: I logged in on google instead of the app and it let me change stuff!

.... How do I close this since the issue is resolved?