i am getting error in AdminDirectory.Members.insert(member, groupEmail);

Failed with error API call to directory.members.insert failed with error: Resource Not Found: groupKey

not able to add users to google group

please help!

function myFunction() {  
  addMembersFromSheet();
}
function addMembersFromSheet() {
  var sheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName("groups");

  // var emails = sheet.getRange(1,1,sheet.getLastRow()-1,1).getValues();
  var emails = SpreadsheetApp.getActive().getRange("Sheet1!A1:A3").getValues();
  var group = GroupsApp.getGroupByEmail("testingw@googlegroups.com");
for(i = 0; i < emails.length; i++) {
    try {
      addGroupMember(emails[i][0], 'testingw@googlegroups.com');
      console.log(emails[i][0]);
    }
    catch(e) {
      console.error(e);
      continue;
    }   
  }
}
function addGroupMember(userEmail,groupEmail) {  
  const member = {
    email: userEmail,
    role: 'MEMBER'
  };
  try {
    AdminDirectory.Members.insert(member, groupEmail);

    Logger.log('User %s added as a member of group %s.', userEmail, groupEmail);
  } catch (err) {
    // TODO (developer)- Handle exception from the API
    Logger.log('Failed with error %s', err.message);
  }
}