symfony - png file can't be uploaded sonata-media-bundle -


i have set upped sonatamediabundle

i can upload jpg file correctly though,when try upload png file.

it shows error.

an error has occurred during creation of item "n/a". 

my config.yml this. think set png file config correctly. there other check point uploading png??

sonata_media:     # if don't use default namespace configuration     #class:     #    media: myvendor\mediabundle\entity\media     #    gallery: myvendor\mediabundle\entity\gallery     #    gallery_has_media: myvendor\mediabundle\entity\galleryhasmedia     default_context: default     db_driver: doctrine_orm # or doctrine_mongodb, doctrine_phpcr     contexts:         default:  # default context mandatory             providers:                 - sonata.media.provider.dailymotion                 - sonata.media.provider.youtube                 - sonata.media.provider.image                 - sonata.media.provider.file              formats:                 small: { width: 100 , quality: 70}                 big:   { width: 500 , quality: 70}      cdn:         server:             path: /myapp/web/uploads/media # not need change depending on server...      filesystem:         local:             directory:  %kernel.root_dir%/../web/uploads/media             create:     false     providers:         image:             service:    sonata.media.provider.image             resizer:    sonata.media.resizer.simple # sonata.media.resizer.square             filesystem: sonata.media.filesystem.local             cdn:        sonata.media.cdn.server             generator:  sonata.media.generator.default             thumbnail:  sonata.media.thumbnail.format             allowed_extensions: ['jpg', 'png', 'jpeg']             allowed_mime_types: ['image/pjpeg', 'image/jpeg', 'image/png', 'image/x-png'] 

you have check form: configureformfields()

the error catch there:

// show error message if form failed validation         if (!$isformvalid) {             if (!$this->isxmlhttprequest()) {                 $this->addflash('sonata_flash_error', $this->admin->trans('flash_create_error', array('%name%' => $this->admin->tostring($object)), 'sonataadminbundle'));             }         }