reader is a personal project. Support is limited but issues are taken seriously.
Google sign-in tokens expire periodically. The extension will attempt to refresh your session automatically. If it cannot, closing and reopening the popup and signing in again will resolve it.
Processing typically takes a few minutes depending on article length. If your feed has not updated after 15 minutes, the article may have been too long or the page may not have had extractable text content (paywalled articles, PDFs, and pages that require JavaScript to render are not currently supported).
Try refreshing the page. If the issue persists, the audio file may still be processing.
Email edwin.a.avalos@gmail.com for help or to report an issue.