This happens when a submitter uploads files with a total size larger than 5MB. In this case, you will not receive the attachments in your mailbox, but the direct download links. Click on them to download files.
In the Upload Storage section of your CaptainForm account, you can view all the files that have been uploaded from all your online forms. If you check one file you have the option to select all the files received through all your forms. If you need to delete only the files received from a specific form, check the box next to the form’s name. All files are archived in a .zip file, so you’ll need to unzip them on your device with the help of a dedicated software (e.g. 7-zip). You’ll find the .zip file by the name “archive_[your-username]”.