Why am I getting this error: "Static method cannot be referenced from a non static context: void EMedCalloutsExtension.makePostCallout1(List<Id>)" ?

The error appears when I try to save this test class:
@isTest
private class EmedscalloutTest2 {
     @isTest static void testCallout() {
         date d = date.today();
         lead l = new lead(firstname = 'test', lastname = 'test', patient_dob__c = d);
         insert l;
         list<string> refids = new list<string>();
         refids.add(l.id);
         
        // Set mock callout class 
        Test.setMock(HttpCalloutMock.class, new EmedsCalloutTest());
        
        // Call method to test.
        // This causes a fake response to be sent
        // from the class that implements HttpCalloutMock. 
        EMedCalloutsExtension tw = new EMedCalloutsExtension();
        tw.makePostCallout1(refids);

    }
}


Here is my first test class/method:
@isTest
global class EmedsCalloutTest implements HttpCalloutMock {
    // Implement this interface method
    global HTTPResponse respond(HTTPRequest req) {
        // Optionally, only send a mock response for a specific endpoint
        // and method.
        System.assertEquals('http://example.com/example/test', req.getEndpoint());
        System.assertEquals('GET', req.getMethod());
        
        // Create a fake response
        HttpResponse res = new HttpResponse();
        res.setHeader('Content-Type', 'application/json');
        res.setBody('{"example":"test"}');
        res.setStatusCode(200);
        return res;
    }
}


and my actual code:
trigger  ReferralCreateContact on Lead (after insert, after update) {
if(!Test.isRunningTest()) { 
    if (trigger.isInsert){
     List<string> leadIds = new List<string>();
    for (lead ref : trigger.new){
      if(System.IsBatch() == false && System.isFuture() == false){ 
        if (ref.Epaces_Checked__c != true){
          lead newl = new lead();
          newl.Id = ref.id;
          leadIds.add(newl.id);
        EMedCalloutsExtension.makePostCallout1(leadIds); 
        }
      }}} }
public class EMedCalloutsExtension {
    static string EmedrequestId;
    static string requestStatus;
    
@future(callout = true)
public static void  makePostCallout1(list<id> refIds) {
    
  List <Lead> refs =[Select Id, firstname, lastname, gender__c, patient_dob__c, patient_ssn__c, Epaces_Checked__c, Emed_Request_Id__c, medicaid_id__c, medicare_id__c from Lead where Id in :refIds]; 
     List<lead> refToUpdate = new List<Lead>();      
           for (lead ref : refs){

 //Set up reassignment of static resource string items              
   String ssnReplace; 
           if (ref.Patient_SSN__c != null){
            ssnReplace = ref.Patient_SSN__c.replace('-','');
           }
    String genderLetter;
           if (ref.Gender__c == 'Male'){
               genderLetter = 'M';
           } else if (ref.Gender__c == 'Female'){
               genderLetter = 'F';
           }
           
           String first;
           String second;
           String third;
            String d = String.valueOf(ref.Patient_DOB__c);
           system.debug('***dob string raw: ' + d);
                first = d.substring(0,4);
                second = d.substring(5,7);
                third = d.substring(8,10);
           String dob = first + second + third;
           system.debug('***dob formatted: ' + dob);

 
//REQUEST #1          
      string reqbody;
     StaticResource r =[Select Id,Body from StaticResource where Name='EMedCalloutBody' limit 1];
      reqBody=r.body.toString(); 
     // reqBody=reqBody.replace('{{FirstName}}', ref.firstname);     
     // reqBody=reqBody.replace('{{LastName}}', ref.lastname);  
               if (ref.Medicaid_ID__c != null){
     // reqBody=reqBody.replace('{{MedicaidId}}', ref.medicaid_id__c); 
      reqBody = reqBody.replace('{{residentInfo}}', '{"first_name": "'+ ref.firstname +'", "last_name": "' + ref.lastname +'", "id_type":"MI", "subscriber_id":"' + ref.medicaid_id__c + '"}');             
               } 
               else if (ref.gender__c != null && ref.Patient_DOB__c != null && ref.Patient_SSN__c != null){
                   reqBody = reqBody.replace('{{residentInfo}}', '{"first_name": "'+ ref.firstname +'", "last_name": "' + ref.lastname +'", "gender":"' + genderLetter + '", "birthdate": "' + dob + '", "social_security_number": "' + ssnReplace + '"}');    
               }
       HttpRequest req = new HttpRequest();
           req.setHeader('Content-Type', 'application/json');
                req.setMethod('POST');
                req.setBody(reqBody);
                req.setEndpoint('callout:Emed');
                req.setTimeout(2 * 60 * 1000);
                    system.debug('ENDPOINT: ' + req.getendpoint());
                       system.debug('BODY: '+ req.getBody());
         Http http = new Http();
           HttpResponse response = http.send(req);
        if (response.getStatusCode() != 200) {
            System.debug('The status code returned was not expected: ' +
                response.getStatusCode() + ' ' + response.getStatus());
        } else {
            system.debug(response.getstatuscode());
           System.debug(response.getBody());
             string requestId = response.getbody().substringAfter('"request_id": ').substringBefore(',');
      //      ref.Emed_Request_Id__c = requestId;
            EmedrequestId = requestId;
            

              string reqbodyResp;   
              StaticResource r2 =[Select Id,Body from StaticResource where Name='EmedResponseBody' limit 1];
               reqbodyResp=r2.body.toString();
              reqbodyResp=reqbodyResp.replace('{{requestId}}', EmedrequestId);
               
               HttpRequest req2 = new HttpRequest();
                  req2.setHeader('Content-Type', 'application/json');
                req2.setMethod('POST');
                req2.setBody(reqbodyResp);
                req2.setEndpoint('callout:Emed_Response');
                req2.setTimeout(2 * 60 * 1000);
                        system.debug('ENDPOINT2: ' + req2.getendpoint());
                        system.debug('BODY2: '+ req2.getBody());
                  Http http2 = new Http();
                 HttpResponse response2 = http2.send(req2);
               
        if (response2.getStatusCode() != 200) {
            System.debug('The status code returned was not expected: ' +
                response2.getStatusCode() + ' ' + response2.getStatus());
        } else {
            system.debug(response2.getstatuscode());
           System.debug(response2.getBody());
            Id refId = ref.id;
            // instantiate a new instance of the Queueable class
            EmedFollowupCallout makeAnotherFollowUp = new EmedFollowupCallout(response2.getBody(), refId, requestId);
            // enqueue the job for processing
            ID jobID = System.enqueueJob(makeAnotherFollowUp);

           } 
 
        }
          return;
    } 
}
   
}