"message": "Unable to open file for reading [/public/storage/shipments/CJ2K4u6S6uluEGd8spOdYgwNkg8NgLFoC6cF6fm5.pdf]",

    "exception": "Swift_IoException",

    "file": "E:\\webserver\\htdocs\\truckin\\vendor\\swiftmailer\\swiftmailer\\lib\\classes\\Swift\\ByteStream\\FileByteStream.php",

    "line": 131,

<?php

namespace App\Mail;

use Illuminate\Bus\Queueable;

use Illuminate\Mail\Mailable;

use Illuminate\Queue\SerializesModels;

use Illuminate\Contracts\Queue\ShouldQueue;

use App\Shipment;

use App\Shipment_Attachment;

class shipmentAttachments extends Mailable

{

    use Queueable, SerializesModels;

    /**

     * Create a new message instance.

     *

     * @return void

     */

    public $shipment, $attachment, $storagePath;

    public function __construct($shipment, $attachment, $storagePath)

    {

        $this->shipment = $shipment;

        $this->attachment = $attachment;

        $this->attachmentFile = '/public'.$storagePath;

        $this->proNumber = $shipment->pro_number;

    }

    /**

     * Build the message.

     *

     * @return $this

     */

    public function build()

    {

         return $this->from('billing@cmxtrucking.com')

                    ->cc('billing@cmxtrucking.com')

                    ->subject('New Attachment(s) - '. $this->proNumber)

                    ->view('emails.shipments.shipmentAttachments',['shipment'=> $this->shipment])

                    ->attach($this->attachmentFile);

    }

}

public function attachmentsEmail(Request $request){

        $shipment = Shipment::findOrFail($request->shipmentID);

        $attachment = Shipment_Attachment::findOrFail($request->attachmentID);

        $storagePath = Storage::url($attachment->attachmentPath);

        $email = $request->email;

             Mail::to($email)->send(new shipmentAttachments($shipment, $attachment, $storagePath));  //maybe try to use queue instead of send...

        return back();

    }

Try to use public_path() laravel helper function instead of '/public'.

$this->attachmentFile = public_path() . '/' . $storagePath;  亲测可行

Maybe you need to change this variable in public/index.php. I have right below the require bootstrap:

$app->bind('path.public', function() {

    return __DIR__;

});

Make some tests.

dd(public_path());

dd(public_path() . '/' . $storagePath);

Or maybe verify if file exist with FileSystem class.

Hope this help you!