monitor shards servers with mongostat

when trying to monitor shard server with mongostat trigger the following error:
failed to connect to mongodb://server1:27017,server2:27017,server3:27017/admin?authSource=admin: connection() error occurred during connection handshake: auth error: sasl conversation error: unable to authenticate using mechanism “SCRAM-SHA-1”: (AuthenticationFailed) Authentication failed.
Where server1, server2 ,server3 are a shard cluster

our connection string is:
mongostat --username admin --password mypwd mongodb://s-nal-pro-mg-04:27017,s-nal-pro-mg-05:27017,s-nal-pro-mg-06:27017/admin?authSource=admin

How can be fix this error to monitor our shard clusters?