Unable to enable sharding in mongodb

We have created 3 shards and each shard has 2 replicas with mongodb version 3.6.21. Then we created an admin user with root privileges in the primary node of each shard on different nodes. We are able to log in to the mongod service directly by using user/pass auth. Now we would like to enable sharding on an application dB and for that, we are using the below commands.

[root@MONGODB01 ~]# mongo --port 27017
MongoDB shell version v3.6.21
connecting to: mongodb://127.0.0.1:27017/?gssapiServiceName=mongodb
Implicit session: session { "id" : UUID("45c58424-422c-4a73-9d18-027718aa0a36") }
MongoDB server version: 3.6.21
mongos> use dsyh_mongo
switched to db dsyh_mongo
mongos> sh.enableSharding("dsyh_mongo")
{
        "ok" : 0,
        "errmsg" : "not authorized on admin to execute command { enableSharding: \"dsyh_mongo\", lsid: { id: UUID(\"45c58424-422c-4a73-9d18-027718aa0a36\") }, $clusterTime: { clusterTime: Timestamp(1634624354, 1), signature: { hash: BinData(0, 3F3BBFE3DD659B7E0FAEE493345496D9DAB9B2A4), keyId: 7020363352299798554 } }, $db: \"admin\" }",
        "code" : 13,
        "codeName" : "Unauthorized",
        "operationTime" : Timestamp(1634624352, 1),
        "$clusterTime" : {
                "clusterTime" : Timestamp(1634624354, 1),
                "signature" : {
                        "hash" : BinData(0,"Pzu/491lm34PruSTNFSW2dq5sqQ="),
                        "keyId" : NumberLong("7020363352299798554")
                }
        }
}

But we are facing the above error. Here mongos is running on port 27017 and mongodb is running on port 37017 on the same server Please suggest what went wrong here as we were able to use similar steps earlier?