Yahoo has started to block users from accessing its email services if customers are using ad-blockers in their browser.
The company is currently rolling out a "new product experience" in the US, with users reporting that Yahoo Mail asked them to turn off their blocker before being able to access their accounts.
The message says: "Uh oh… We are unable to display Yahoo Mail. Please disable Ad Blocker to continue using Yahoo Mail."
Advertiser revenues from online marketing are in free fall as reports suggest they are facing a $21.8 billion loss in revenue this year due to ad blocking. The lost revenue globally is expected to reach $41.4bn in 2016.
Users took to social media to show their frustration with the company’s move.
A member of an ad blocking forum said: "Because we, the users, are getting smarter, they [Yahoo] need to change avenues of making money or providing content to their users. The internet is changing fast, so they will have to adapt or die.
"At the end of the day, it is up to Yahoo, to figure that part out. If any email service paid or free, held users emails hostage, they deserve to go out of business. Do they really think they can force users to disable ABP, on Yahoo’s sites?"