The U.S. Supreme Court has denied Google’s appeal to stop a class action lawsuit filed by California advertisers.

The advertisers claimed that the internet giant misled them about where their ads would be featured through Google AdWords, a service aimed at placing ads next to relevant Google Internet search results. The advertisers, who used AdWords from 2004 through 2008, said they were not informed that the ads would also appear on error pages and undeveloped websites, violating California’s fair advertising laws.

In 2012, a federal judge ruled that the advertisers couldn’t file a class action suit because each advertiser would have paid a different sum for the ads. In 2011, as a result of employees bringing claims against Walmart, a U.S. Supreme Court precedent was set that class actions can move forward only if each plaintiff has a similar claim and that claim can be resolved on a class-wide basis.

However, the San Francisco-based 9th U.S. Circuit Court of Appeals overturned the federal judge’s decision in September of 2015. Google appealed the ruling, but the Supreme Court has decided to let the ruling stand.

This is only the most recent advertising conflict for Google. In April of 2015, the European Union laid out antitrust charges against the Silicon Valley juggernaut, claiming that Google unfairly promotes its own services to consumers in search results.

Advertising remains the foundation of Google’s financial success, making up 89.9% of company revenue in 2015 according to an SEC-mandated earnings report released in January.