I can't activate my PS4 the same way anymore

So I share my PS plus with my cousin and everything was fine, i was able to activate and deactivate whenever i wanted, but recently, everytime I try to do so, i can't. As soon as I click ''change to this PS4'' i get this NP-41772-1 error saying that the only way I can activate my account is to deactivating it from the other system, are there any fixes for it? bc now i have to keep messaging my cousin to deactivate the account and it's very annoying. I checked other posts regarding errors like this in this sub but havent found anything

Thanks in advance!