Survival rank upgrades

hi i am NetheriteBlock_

i can not buy a rank upgrade for my friend vincent_nl
i do not no why but it is not possible
who knows how i can buy a rank upgrade for vincent_nl
let me now

bye NethetiteBlock_

Did he get a rank from a voucher? Cuz u can't upgrade those than u need to buy the rank and not upgrade

i dont know

ask the man if his rank is from a voucher as someone has mentioned also what you tryna upgrade to