OJS 3.4.0-7 | Error when sending a new academic article

For new submissions, in the final step, when an author clicks the Submit button, a new modal window appears, but the submission is not clearly confirmed.


PHP error log:

[22-Nov-2024 18:06:46 America/Mexico_City] Slim Application Error:
Type: TypeError
Message: get_class(): Argument #1 ($object) must be of type object, null given
File: /var/www/html/lib/pkp/classes/mail/Mailer.php
Line: 79
Trace: #0 /var/www/html/lib/pkp/classes/mail/Mailer.php(79): get_class()
#1 /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Mail/Mailer.php(239): PKP\mail\Mailer->renderView()
#2 /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Mail/Mailable.php(281): Illuminate\Mail\Mailer->render()
#3 /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Support/Traits/Localizable.php(19): Illuminate\Mail\Mailable->Illuminate\Mail{closure}()
#4 /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Mail/Mailable.php(278): Illuminate\Mail\Mailable->withLocale()
#5 /var/www/html/lib/pkp/classes/log/SubmissionEmailLogDAO.php(89): Illuminate\Mail\Mailable->render()
#6 /var/www/html/lib/pkp/classes/observers/listeners/AssignEditors.php(121): PKP\log\SubmissionEmailLogDAO->logMailable()
#7 /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Events/Dispatcher.php(441): PKP\observers\listeners\AssignEditors->handle()
#8 /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Events/Dispatcher.php(249): Illuminate\Events\Dispatcher->Illuminate\Events{closure}()
#9 /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Foundation/helpers.php(451): Illuminate\Events\Dispatcher->dispatch()
#10 /var/www/html/lib/pkp/classes/submission/Repository.php(593): event()
#11 /var/www/html/lib/pkp/api/v1/submissions/PKPSubmissionHandler.php(724): PKP\submission\Repository->submit()
#12 [internal function]: PKP\API\v1\submissions\PKPSubmissionHandler->submit()