Hello,I initially appended my message at the end of http://www.forum.osticket.com/d/discussion//open-a-new-ticket-always-returns-500-internal-server-error-invalid-csrf-token-on-ticket-response before I notice it was an old thread with less chance to be viewed. So, I open this new one.Well, I'm with osTicket 1.9.14 (entire system info at bottom).Just after a ticket submission, my customers (and my test shows the same

thing) obtain an error 500 about

http://<my-domain>/support/open.php. Here is the exact message (just masked my domain name):The <my_domain> page isn’t working.<my_domain> is currently unable to handle this request.HTTP ERROR 500Nothing in osTicket's System log visible from http://<my_domain>/support/scp/logs.php.Here is what I see in http://<my_domain>/support/error_log: PHP Fatal error: Uncaught exception

'Exception' with message 'No such backend registered' in

/home/biiip/public_html/sfy/support/include/class.file.phpStack trace:#0 /home/biiip/public_html/sfy/support/include/class.file.php(111): FileStorageBackend:(Object(AttachmentFile))#1 /home/biiip/public_html/sfy/support/include/class.file.php(115): AttachmentFile->open()#2 /home/biiip/public_html/sfy/support/include/class.file.php(133): AttachmentFile->sendData(false)#3 /home/biiip/public_html/sfy/support/include/class.mailer.php(373): AttachmentFile->getData()#4 : Mailer->{closure}(Array)#5

/home/biiip/public_html/sfy/support/include/class.mailer.php(379):

preg_replace_callback('/cid:({32...', Object(Closure), '<div

style="dis...')#6

/home/biiip/public_html/sfy/support/include/class.email.php(168):

Mailer->send('admin.alerts@sh...', 'New Ticket Aler...',

'<h2>Hi Admin,</...', Array)#7

/home/biiip/public_html/sfy/support/include/class.email.php(178):

Email->sen in

/home/biiip/public_html/sfy/support/include/class.file.php on line 693And here is the access log for the domain just before the error:78.218.191.79

- - "GET /support/ajax.php/config/client

HTTP/1.1" 200 69 "http://<my_domain>/support/open.php"

"Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like

Gecko) Chrome/56.0.2924.87 Safari/537.36"78.218.191.79 - -

"GET

/support/ajax.php/draft/ticket.client.9b41d9ff842e HTTP/1.1" 205 33

"http://<my_domain>/support/open.php" "Mozilla/5.0 (Windows NT