Google-script; Conversion from the format application / octet-stream to application / pdf is not sup

First of all my first code works. However, if there is more than one attachment in email, you will have problems I had originally. Solution below:

function searchEmails() {

  var threads = GmailApp.search('in:inbox newer_than:6d');

    if (threads.length > 0) {
      for (var t=threads.length-1; t>=0; t--) {
        var msgs = GmailApp.getMessagesForThreads(threads);    

        for (var i = 0 ; i < msgs.length; i++) {    
          for (var j = 0; j < msgs[i].length; j++) {      
            var attachments = msgs[i][j].getAttachments();                

            for (var k = 0; k < attachments.length; k++) {          
              var content = attachments[k].getContentType();                
              Logger.log(attachments[k].getName()) //check file extension

            if (content == 'application/pdf'){
               

/* 
you can check if the attachment has the expected name
              var attachmentsName = attachments[k].getName();
              if (attachmentsName == 'looking name'){
*/

              var blob = attachments[k].getAs(MimeType.PDF);            
              var filetext = pdfToText(blob);            
              filetext = filetext.substr(filetext.search("SZCZEGÓŁY"));            
              filetext = filetext.split(' ');                        
              var msgValue = filetext[14] + filetext[15];            
              var msgDate = filetext[6];            
              var type = filetext[3];            

   // rest of my code

function pdfToText (blob, options) {

  options = options || {};
  var parents = [];
  if (options.path) {
    parents.push(getDriveFolderFromPath(options.path));
  }
  var pdfName = blob.getName();
  var resource = {
    title: pdfName,
    mimeType: blob.getContentType(),
    parents: parents
  };

  // Save PDF as GDOC
  resource.title = pdfName.replace(/pdf$/, 'gdoc');
  var insertOpts = {
    ocr: true,
    ocrLanguage: options.ocrLanguage || 'pl'
  }
  var gdocFile = Drive.Files.insert(resource, blob, insertOpts);

  // Get text from GDOC  
  var gdocDoc = DocumentApp.openById(gdocFile.id);
  var text = gdocDoc.getBody().getText();

  // Delete document.
  if (!options.keepGdoc) {
    Drive.Files.remove(gdocFile.id);
  }

  return text;
}

function getDriveFolderFromPath (path) {
  return (path || "/").split("/").reduce ( function(prev,current) {
    if (prev && current) {
      var fldrs = prev.getFoldersByName(current);
      return fldrs.hasNext() ? fldrs.next() : null;
    }
    else { 
      return current ? null : prev; 
    }
  },DriveApp.getRootFolder()); 
}