There are several steps to troubleshoot large file attachment issues when sending emails:

1. Make sure you are not exceeding the size limit for the file attachments. This is often set by your email provider or can be adjusted in your account settings.
2. Check your internet connection. Poor or weak connection can interrupt the download of large attachments.
3. Verify the recipient’s email for possible errors.
4. If needed, compress the file into a ZIP folder to reduce its size.
5. If the problem persists, contact your email provider for further assistance.