As it looks for new ways to make money after years of massive growth, the company is trying to charge people for sharing accounts.
In order to add a second home to their accounts, subscribers in five countries in central and South America will have to pay an extra fee.
Password sharing will be spread around the world.
Its results are due on Tuesday.
The first subscriber fall in more than a decade happened earlier this year. The fall off in subscribers is expected to be revealed when the firm gives an update on its members.
It is a stark reversal for a company that for years saw seemingly unstoppable growth as it changed the way people consume entertainment.
When the Pandemic hit in 2020 and people were stuck at home, they went to its shows.
As pre-pandemic habits return, it's difficult to get new sign-ups and keep existing members happy.
Price hikes have prompted people in countries such as the UK to cancel subscriptions, while a raft of new competitors, like Disney, lure people in the US and elsewhere to switch to them.
People are signing up to watch certain shows and then canceling their accounts, according to research.
Families are not sure how to respond to the firm's request for more money.
In March of this year, it was announced that households in certain countries would be charged for an extra member.
The latest move, which comes into effect from next month in Argentina, Honduras, Guatemala, El Salvadoran and the Dominican Republic, presents the request in slightly different terms, asking for $2.99 for each additional home.
People can change their account at any time.
The charges will be rolled out globally as soon as the end of the year, according to the company.
The firm will experiment with a lower-cost ads-based service in order to get more money out of existing audiences.