Regarding Google Apps Script taking a long time to process doPost, doPost is called again

function doPost(){

  // var lock = LockService.getUserLock(); 
  var lock = LockService.getScriptLock(); 
  var success=lock.tryLock(3);
  If(!success){// If the lock is not released within 3 seconds, it is determined that the previous processing has not been completed.
    console.error('doPost was called while processing doPost.');
    outHtml=HtmlService.createTemplateFromFile("Wait a minute.");
    return outHtml.evaluate();
  }

  try{
    Utilities.sleep (180000);
  }
  US>finally
    lock.releaseLock();  
  }