Telegram operates five data centers (DCs): DC1 and DC3 in Miami, DC2 and DC4 in Amsterdam, and DC5 in Singapore. Accounts are assigned to a DC at registration based on phone country code and cannot switch. DC5 is notorious in the Chinese community for frequent outages, leaving +86 users unable to connect while +1 users on DC1 and European users on DC4 enjoy stability.

A bot querying user DCs found 360 on DC1, 50 on DC4, 390 on DC5, but zero on DC2 or DC3. This sparked speculation that DC2/DC3 were subordinate or empty. However, DC2 actually serves many users (e.g., +49 Germany); the bot's Web CDN method misidentifies DC2 as DC4 and DC3 as DC1 because they share CDN domains.

Three methods determine a user's DC: the login method (PHONE_MIGRATE_X error), the profile picture/file method (dc_id field), and the flawed Web CDN method. Testing 10,000+ numbers via the login method confirmed DC3 hasn't accepted new registrations since ~2020; existing DC3 users were likely migrated to DC1. DC2 remains active with substantial users, while DC3 appears functionally empty.