"502. That's an error. The server encountered a temporary error and could not complete your request. Please try again in 30 seconds. That's all we know," reads the message on the error page.
Sources said that the 502 error generally occurs due to poor IP communication between servers. Earlier also Google users have encountered a smilier error but it seems to be the first time when its has affected a multitude of Google services.
Meanwhile, Google users have not been completely cut-off from Google services but acess is irregular.