I’ve already attempted to download my attachments. The attachments will download for a while and then suddenly quit. I have deleted my history, cookies, etc… but that did not work.
How do I download my attachments from Yahoo Mail?
Try downloading your attachments using browser's native download manager and not from third party ones to see if it helps.
Problems attaching or downloading files in Yahoo Mail
changed yahoo to basic mail, to check if you can download the attachment. then switch to the new interface.