Alibaba CEO Daniel Zhang on Thursday sent a solemn-toned internal email to Alibaba Cloud staff right after he announced changes to the company’s leadership, according to The Economic Observer. Zhang replaced former unit head Zhang Jianfeng to become the new head of Alibaba Cloud on the same day. In the email, Zhang reminded staff that “accumulated trust from clients” is the cloud computing unit’s core competitive power. “Once we lose that trust, clients can leave us anytime,” the email said. On Dec. 18, Alibaba Cloud experienced a widespread outage in Hong Kong due to cooling system malfunctions. Meanwhile, Alibaba’s cloud unit has seen slower quarterly growth this year and is facing intense competition from Huawei Cloud, Tencent Cloud, and the cloud computing arms of China’s state telecom providers Unicom and China Telecom. [The Economic Observer, in Chinese]