Hi,

I am getting 401 unauthorized error while running my API. I have checked the endpoint url and all credentials from server side, all are correct. Still getting this error. 
Error: [Status=Unauthorized, StatusCode=401]
"code":401,"message":"An error occurred. Header not set."
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This is my code:

public class QcAPI {
    @future(callout=true)
    public static void callServer(String id){
        Opportunity opp =[Select Id,Account.FirstName,Account.ShippingAddress,Account.BillingAddress, Account.LastName,Email__c,DUP_Mobile__c,account.BillingStreet,account.BillingCity,account.BillingState,account.BillingCountry,account.BillingPostalCode,
                          account.ShippingStreet,account.ShippingCity,account.ShippingState,account.ShippingCountry,account.ShippingPostalCode from Opportunity where id=: id limit 1];
        
        OpportunityDataWrap oppdata = new OpportunityDataWrap();
        String rno = opp.Account.LastName+'-'+opp.Id;
        oppdata.refno = rno;
        oppdata.syncOnly = true;
        oppdata.deliveryMode = 'API';
        
        if(opp.Account.ShippingAddress !=null){
            ShippingAddressWrap cc = new ShippingAddressWrap();
            cc.firstname = opp.Account.LastName;
            cc.lastname = '';
            cc.email = opp.Email__c;
            cc.telephone = '+91'+opp.DUP_Mobile__c;
            cc.country = 'IN';
            cc.line1 = opp.Account.ShippingStreet;
            cc.line2 = '-';
            cc.city = opp.Account.ShippingCity;
            cc.postcode = opp.Account.ShippingPostalCode;
            cc.region = opp.Account.ShippingState;
            cc.billToThis = true;
            oppdata.address = cc;
        }
        
        if(opp.Account.BillingAddress !=null){
            BillingAddressWrap cb = new BillingAddressWrap();
            cb.firstname = opp.Account.lastname;
            cb.lastname = '';
            cb.email = opp.Email__c;
            cb.telephone = '+91'+opp.DUP_Mobile__c;
            cb.country = 'IN';
            cb.line1 = opp.Account.ShippingStreet;
            cb.line2 = '-';
            cb.city = opp.Account.ShippingCity;
            cb.postcode = opp.Account.ShippingPostalCode;
            cb.region = opp.Account.ShippingState; 
            oppdata.billing = cb;
        }
        List<paymentwrap> pw = new List<paymentwrap>();
        paymentwrap pwr = new paymentwrap();
        pwr.code = 'xyz';
        pwr.amount = 0;
        pw.add(pwr);
        oppdata.payments = pw;
        
        List<productsWrap> prodwrap = new List<productsWrap>();
        productsWrap pdwr = new productsWrap();
        pdwr.sku = 'xyzABCDE000';  
        pdwr.price = 0;
        pdwr.qty = 1;
        pdwr.currency_x =356;
        pdwr.giftMessage ='';
        pdwr.theme ='';
        prodwrap.add(pdwr);
        oppdata.products = prodwrap;
        system.debug('OppData:'+oppdata);
        String jsbody = JSON.serialize(oppdata);
        String jsonBody = jsbody.replace('currency_x', 'currency');
        system.debug('JSON BODY : '+jsonBody);
        map<string,Object> result = (map<string,Object>)JSON.deserializeUntyped(jsonBody);
        system.debug('result '+result);
        string endresult = JSON.serialize(result);
        system.debug('endresult '+endresult);

        String customLabelValue = Label.QCAPI+'/orders';
        //signature calling
        
        XYZ__c    Qc = XYZ__c.getvalues('XYZ details');
        string secretKeyValue = Qc.Consumer_secret__c;
        string reqMethod = 'POST';
        string url = EncodingUtil.URLEncode(Label.QCAPI+'/10000028/resend','UTF-8');
        system.JSONParser requestData = JSON.createParser(jsonBody);
        string endpoint = reqMethod + '&' + url;
        system.debug('end point url '+endpoint);
        string signature;
        Blob hmacData = Crypto.generateMac('HmacSHA512', Blob.valueOf(endpoint), Blob.valueOf(secretKeyValue));
        signature = encodingUtil.convertToHex(hmacData);
        system.debug('signature '+signature);
        
        string BearerToken = QCoauth.BearerToken();
        HttpRequest request = new HttpRequest();
        request.setEndpoint(customLabelValue);
        request.setMethod('POST');
        request.setHeader('Content-Type', 'application/json');
        request.setHeader('Authorization',BearerToken);
        request.setHeader('Accept','*/*');
        request.setBody(jsonBody);
        Http http = new Http();
        HttpResponse response = http.send(request);
        system.debug('get response :'+response.getBody());
        system.debug('get response :'+response);
        List<ResponseData> rd = (List<ResponseData>)JSON.deserialize(response.getBody(),List<ResponseData>.class);
        System.debug('Response Data :'+rd);
        
    }
    
    public class ShippingAddressWrap{
        public String firstname{get;set;}
        public String lastname{get;set;} 
        public String email{get;set;} 
        public String telephone{get;set;} 
        public String line1{get;set;} 
        public String line2{get;set;} 
        public String city{get;set;} 
        public String region{get;set;} 
        public String country{get;set;} 
        public String postcode{get;set;} 
        public boolean billToThis{get;set;} 
    }
    
    public class BillingAddressWrap{
        public String firstname{get;set;}
        public String lastname{get;set;} 
        public String email{get;set;} 
        public String telephone{get;set;} 
        public String line1{get;set;} 
        public String line2{get;set;} 
        public String city{get;set;} 
        public String region{get;set;} 
        public String country{get;set;} 
        public String postcode{get;set;} 
    }
    public class paymentwrap{
        public string code{get;set;}
        public double amount{get;set;}
    }
    public class productsWrap{
        public string sku{get;set;}
        public double price{get;set;}
        public integer qty{get;set;}
        public integer currency_x{get;set;}
        public string giftMessage{get;set;}
        public string theme{get;set;}
    }
    public class OpportunityDataWrap{    
        Public ShippingAddressWrap address{get;set;}
        Public BillingAddressWrap billing{get;set;}
        Public List<paymentwrap> payments{get;set;}
        public string refno{get;set;}
        public List<productsWrap> products{get;set;}
        public boolean syncOnly{get;set;}
        public String deliveryMode{get;set;} 
    }
    public class ResponseData {
        public string status;
        public List<cardwrap> cards;
    }
    public class cardwrap{
        public string cardNumber;
        public string cardPin;
    }
}
-----------
This is my Oauth code:

public class qcOauth {
    public static string AuthCode(){
        string Authcode;
        qc__c    Qc = qc__c.getvalues('qc details');
        authWrapreq Aw = new authWrapreq();
        Aw.clientId = Qc.Consumer_Key__c;
        Aw.username = Qc.UserName__c;
        Aw.password = Qc.Password__c;
        
        string endpoint = Qc.url__c+'verify';
        HttpRequest request = new HttpRequest();
        request.setEndpoint(endpoint);
        request.setMethod('POST');
        request.setHeader('Content-Type', 'application/json');
        String jsonBody = JSON.serialize(Aw);
      //  system.debug('JSON BODY : '+jsonBody);
        request.setBody(jsonBody);
        Http http = new Http();
        HttpResponse response = http.send(request);
     //   system.debug('response body: '+response.getBody());
        if(response.getStatusCode() == 200){
            authRes res = (authRes)json.deserialize(response.getBody(), authRes.class);
            authcode = res.authorizationCode;
        }
     //   system.debug(authcode);
        return authcode;
    }
    
    public static string BearerToken(){
        string BearerToken;
        qc__c    Qc = qc__c.getvalues('qc details');
        BearerWrapReq Bw = new BearerWrapReq();
        Bw.clientId = Qc.Consumer_Key__c;
        Bw.clientSecret = Qc.Consumer_secret__c;
        Bw.authorizationCode = Authcode();
        
        string endpoint = Qc.url__c+'token';
        HttpRequest request = new HttpRequest();
        request.setEndpoint(endpoint);
        request.setMethod('POST');
        request.setHeader('Content-Type', 'application/json');
        String jsonBody = JSON.serialize(Bw);
    //    system.debug('JSON BODY : '+jsonBody);
        request.setBody(jsonBody);
        Http http = new Http();
        HttpResponse response = http.send(request);
     //   system.debug('response body: '+response.getBody());
        if(response.getStatusCode() == 200){
            BearRes res = (BearRes)json.deserialize(response.getBody(), BearRes.class);
            BearerToken = res.token;
        }
     //   system.debug(BearerToken);
        return BearerToken;
    }

    public class authWrapreq{
        public string clientId;
        public string username;
        public string password;
    }
    public class authRes{
        public string authorizationCode;
    }
    public class BearerWrapReq{
        public string clientId;
        public string clientSecret;
        public string authorizationCode;
    }
    public class BearRes{
        public string token;
    }
}


Any idea to resolve this issue?

Thanks,
Kezia