Problem uploading bigger files (+20mb)

I have a problem with a script I have bought it from codecanyon and devdojo is the creator of the script. Since he closed the support from codecanyon, I'm gonna ask here and please I NEED HELP to fix this problem .. When I upload files between 1 kb to 19 mb the process is completed, but when the file has 21 mb or 100 mb I get this error :

Whoops, looks like something went wrong.

1/1 TokenMismatchException in VerifyCsrfToken.php line 53: in VerifyCsrfToken.php line 53 at VerifyCsrfToken->handle(object(Request), object(Closure)) at call_user_func_array(array(object(VerifyCsrfToken), 'handle'), array(object(Request), object(Closure))) in Pipeline.php line 124 at Pipeline->Illuminate\Pipeline{closure}(object(Request)) in ShareErrorsFromSession.php line 54 at ShareErrorsFromSession->handle(object(Request), object(Closure)) at call_user_func_array(array(object(ShareErrorsFromSession), 'handle'), array(object(Request), object(Closure))) in Pipeline.php line 124 at Pipeline->Illuminate\Pipeline{closure}(object(Request)) in StartSession.php line 62 at StartSession->handle(object(Request), object(Closure)) at call_user_func_array(array(object(StartSession), 'handle'), array(object(Request), object(Closure))) in Pipeline.php line 124 at Pipeline->Illuminate\Pipeline{closure}(object(Request)) in AddQueuedCookiesToResponse.php line 37 at AddQueuedCookiesToResponse->handle(object(Request), object(Closure)) at call_user_func_array(array(object(AddQueuedCookiesToResponse), 'handle'), array(object(Request), object(Closure))) in Pipeline.php line 124 at Pipeline->Illuminate\Pipeline{closure}(object(Request)) in EncryptCookies.php line 59 at EncryptCookies->handle(object(Request), object(Closure)) at call_user_func_array(array(object(EncryptCookies), 'handle'), array(object(Request), object(Closure))) in Pipeline.php line 124 at Pipeline->Illuminate\Pipeline{closure}(object(Request)) in CheckForMaintenanceMode.php line 42 at CheckForMaintenanceMode->handle(object(Request), object(Closure)) at call_user_func_array(array(object(CheckForMaintenanceMode), 'handle'), array(object(Request), object(Closure))) in Pipeline.php line 124 at Pipeline->Illuminate\Pipeline{closure}(object(Request)) at call_user_func(object(Closure), object(Request)) in Pipeline.php line 103 at Pipeline->then(object(Closure)) in Kernel.php line 122 at Kernel->sendRequestThroughRouter(object(Request)) in Kernel.php line 87 at Kernel->handle(object(Request)) in index.php line 54

What should I do ? Thank you !!