I tried to do continuous integration on google cloud containers with the help of Jenkins and all the stages are working fine except kubectl commands. What could be the problem?

error: group map[extensions:0xc820376e00 policy:0xc820376e70
 authentication.k8s.io:0xc820376fc0 :0xc820376b60 
 authorization.k8s.io:0xc820376c40 componentconfig:0xc820376d90 
 batch:0xc820376d20 rbac.authorization.k8s.io:0xc820376ee0 
 federation:0xc820376af0 apps:0xc820376bd0 autoscaling:0xc820376cb0] 
is already registered


[Pipeline] }
[Pipeline] // node
[Pipeline] End of Pipeline
ERROR: script returned exit code 1
Finished: FAILURE