My guess is that this is likely some sort of network interference between whatever machine you are running ReadyAPI on and Couchbase itself. Maybe try setting up a ping that runs while testing and see if the ping times out when the groovy script times out? That might help rule out network problems.
Other than that, you may want to try checking with Couchbase support, as I'm thinking the problem may be there. I see similar threads on their forums and on Stack Exchange.
https://forums.couchbase.com/t/unable-to-connect-to-db-java-util-concurrent-timeoutexception/4471
https://stackoverflow.com/questions/40758934/couchbase-concurrent-timeout-exception-java-sdk
Anyway thanks for reply. I tried different code approach to resolve this issue. Instead of fetching it using JSON code, I used CouchBase queries. It solved my problem.
