There are some situations that can prevent Dropbox Carousel from uploading your photos to your account. To upload photos to Dropbox Carousel, you need to check out the storage space of your account. If there is not enough space to upload all the photos and videos on your phone, then you will need to get more space. Make sure that your mobile phone is fully charged. If not, then you will need to plug your mobile in to charge. Before uploading photos, check out the network connection. If you don't have a network connection, then you will need to reconnect it. Your photos will easily upload when you are connected to Wi-Fi network. So if you are uploading photos automatically through "Backup Options", then set the settings "Wi-Fi" only. Your photos won't upload unless you are connected to Wi-Fi.