Lotus Adapter Service Error

when i config a lotus adapter service with createsessiion,it occurs error as following:
com.wm.pkg.art.error.DetailedSystemException: [ART.117.4002] Adapter Runtime (Adapter Service): Unable to invoke adapter service totalTest.Lotus:createSession.
[ADA.720.600] Lotus Notes Adapter failed to initialize connection: totalTest.adapters:LotusConnection to host: liuxiaoqiang with user: Administrator/camelot. Possible reason: Could not create session, server possibly down. Exception ID: 4062. Exception message: Could not open Notes session.

on my lotus server, the diiop service is stop and then restart ,but it has no effect.can anyone tell me what i should do ?