When I try to connect the mongoDB using the below URI through our internal services 

URI := mongodb://user:pass@hostname:27017/db?w=majority 

//here i get the tls config using our utilities and pass it back here 
clientOpts := options.Client().ApplyURI(URI).SetTLSConfig(&tlsConfig)
client, err = mongo.Connect(ctx, clientOpts)
if err != nil {
    return nil, err
 }

I get the below error 

connection() error occurred during connection handshake: auth error: sasl conversation error: unable to authenticate using mechanism "SCRAM-SHA-256": (AuthenticationFailed) Authentication failed.
 

But am able to access the same URI and connect to DB for our external port that works fine ., Not sure if i'm missing something here ,

In our old mongo global sign mgo driver we used to use something like below

session, err := mgo.DialWithInfo(mongoDBDialInfo) ,
 
where we set the  DialServer info using tls.Dial("tcp",addr.String(), &tlsConfig) and pass it to the DialInfo

currently we are in the process of migrating our code from mgo driver to go official mongo-driver . 

 Can anyone help me with this ?