Failed to acquire machine and run agent within reasonable time (with RHEL 6)

 Module "qt/qtspeech" (8278f9f5d2c9f47233f59ff8af757e0591045895) Failed repeatedly to launch build/test agent:
 reasons:Failed to acquire machine and run agent within reasonable time (attempt: 1, agent: 1510444332-12398)
 Failed to acquire machine and run agent within reasonable time (attempt: 2, agent: 1510444332-12441)
 Failed to acquire machine and run agent within reasonable time (attempt: 3, agent: 1510444332-12469)
 Failed to acquire machine and run agent within reasonable time (attempt: 4, agent: 1510444332-12508)
 Failed to acquire machine and run agent within reasonable time (attempt: 5, agent: 1510444332-12586)
 Failed to acquire machine and run agent within reasonable time (attempt: 6, agent: 1510444332-12666)
 Failed to acquire machine and run agent within reasonable time (attempt: 7, agent: 1510444332-12718)