External screens connected to MacBookPro and its main screen turn off momentarily frequenetly

My Mid 2014 Retina MacBook Pro is connected to two Dell external monitors (U2713HM) via lightening-to-displayport cable

Some day my MBP and the two monitors can momentarily turn off and then turn back on. These error messages appear a lot in the console log:

How can I fix this problem?

OS version: 10.10.1 (OS X Yosemite)