Observing "Failed to execute Transaction" messages in py-tpcc with concurrent threads/clients scenario (>10 threads) on single query node

Observing below failure messages in py-tpcc execution with 10 concurrent client threads .

I don't see any obvious failures/message on the server side . Is there a way to triage it further ? or is it possible to report the reason for failure using REST API ?

"11:18:38 11-03-2020 11:18:38 [execute:070] WARNING: Failed to execute Transaction 'NEW_ORDER':

11:18:38 11-03-2020 11:18:38 [execute:070] WARNING: Failed to execute Transaction 'NEW_ORDER':

11:18:38 11-03-2020 11:18:38 [execute:070] WARNING: Failed to execute Transaction 'NEW_ORDER':" 
 

Cluster Config :

nodes: 4 (kv,n1ql,index colocated)

Total buckets : 9 (standard py-tpcc)

memory_quota : 1000 MB per bucket

Client Thread : 1 

replicas: 0

Below are Jenkins logs for single client thread vs 10 threads(with cb_collect_logs)

http://perf.jenkins.couchbase.com/job/hercules_nest_pytpcc/12/

Client Threads 10 : with "Failed to execute Transaction " errors

http://perf.jenkins.couchbase.com/job/hercules_nest_pytpcc/19/console