The blocking of Apple mobile entertainment services on Thursday in China poses fresh challenges for the tech company as it prepares to report its first-ever drop in iPhone sales, Reuters reports. Investors are sensitive to any signs of trouble in Greater China, the company’s second-largest market by revenue. Apple executives have flagged the growing services business as a potential source of revenue to offset falling phone sales, and the Chinese market is key. Still, the outage is only troubling if it persists. Apple has a strong track record of working with officials in China, but some analysts questioned whether the company may receive a chillier reception in the future.