The team behind secure messaging app Signal says Amazon has threatened to kick the app off its CloudFront web service unless Signal drops the anti-censorship practice known as domain-fronting. Google recently banned the practice, which lets developers disguise web traffic to look like it’s coming from a different source, allowing apps like Signal to evade country-level bans. As a result, Signal moved from Google to the Amazon-owned Souq content delivery network. But Amazon implemented its own ban on Friday. In an email that Moxie Marlinspike — founder of Signal developer Open Whisper Systems — posted today, Amazon orders the organization to immediately stop using domain-fronting or find another web services provider.

Amazon has said that it’s banning domain-fronting so malware purveyors can’t disguise themselves as innocent web traffic. But Signal used the system to provide service in Egypt, Oman, and the United Arab Emirates (UAE), where it’s officially banned. It got around filters by making traffic appear to come from a huge platform, since countries weren’t willing to ban the entirety of a site like Google to shut down Signal.

Now, Marlinspike says that domain-fronting is “largely non-viable” in those countries. “The idea behind domain fronting was that to block a single site, you’d have to block the rest of the internet as well. In the end, the rest of the internet didn’t like that plan,” he writes. While the Signal team is considering options to provide the same service without Amazon or Google domain-fronting, it doesn’t look like there’s an immediate solution on the horizon. “In the meantime, the censors in these countries will have (at least temporarily) achieved their goals. Sadly, they didn’t have to do anything but wait,” says Marlinspike.