MethodNotAllowedHttpException when passing data from form

I am new with laravel/lumen infrastructure. In my website using lumen, i am trying to have a contact form. I know there's a better way to handle email in lumen but since i dont know much with this framework i decided to have my own native php email sender functions and include it in my blade php template. Basically im just doing native php inside blade template. My form has a method of post and will redirect in the same page after they submit. When i tried it i got MethodNotAllowedHttpException error in RoutesRequests.php (line 596). Can anyone help me with this problem. (Let me know what info you needed to help me with this issue)

Thank you