Weedmaps, the popular online marijuana dispensary locator, has turned to a familiar shield to fend off a cease-and-desist threat from state regulators: Section 230 of the Communications Decency Act.

Earlier this month, California’s Bureau of Cannabis Control disclosed it had ordered Weedmaps to stop running ads from sellers that don’t hold and display registered California license numbers. Weedmaps executives fired back this week, saying that while they’re willing to work with the regulators, the state has no legal authority to sanction them.