after upgrade, indexing server fail

Hi All

     My Sentinel upgrade form 7.4.x to sentinel 8.5 , it seem work fine..but I check show much times "Trying to reach Kibina ", and then indexing fail like below

I install new sentinel appliance which has same version , but it not upgraded....the indexing server could work fine.

so this condition seem only upgrade from 7.x version...

Who has similar experience and could provide some suggestion to me ?? thanks!!