When a website goes offline, it's often the result of a DDoS attack, forgotten domain name purchase, or bad programming. For a Chinese website backed by Sequoia Capital, the outage would be more ominous if it was located anywhere but China.

But in China, government intervention is common and is reported to be behind Fenda's downtime.

Fenda, a Sequoia Capital-backed audio-based knowledge sharing platform, has been unavailable since last week, perhaps due to external forces beyond its control, says Chinese media reports. The external forces mostly likely refer to government intervention, as the Chinese media monitoring and control bureau often suspends operations of popular content platforms it deems harmful to society.

Since its launch at the end of May, Fenda has become among the most downloaded mobile apps in China after it invited celebrities to answer questions about their private personal lives.

A month later, Vision Plus Capital; Sequoia Capital; Wang Sicong, the son of Asia's richest man Dalian Wanda Group's chairman Wang Jianlin; and Chinese knowledge sharing platform Luoji Siwei invested US$25 million in a series A round in Fenda.

Since last week, the Fenda app has been offline. Its Wechat public account has also been unavailable. Where has it gone and what happened?

Fenda's assistant chief executive Wu Yunfei told Chinese media that the company is upgrading its social media technology infrastructure, and the app will be back online soon without offering any details of potential date for the relaunch.

Earlier this year, a popular video series produced by a Beijing film student Papi Jiang was ordered to suspend operations and "adjust" its content. The video series was relaunched shortly after with cleaner language and "softer" content.