Getting error while upgrading document db 3.6.0 to 5.0.0

Hello

region:- us-east-1 DB instance:- db.r5.large

while Upgrading the document DB i am getting this error

Cannot modify engine version because cluster is running on an old configuration. First, apply any cluster-level engine pending maintenance actions (such as system-updates). Then, apply any Operating System pending maintenance actions on the instances and then retry the engine version upgrade.

I had follow this article https://docs.aws.amazon.com/documentdb/latest/developerguide/docdb-mvu.html

please help me out with this Thanks