Attachment failures usually come down to size, file type, or a connection hiccup. Here’s how to work through each possibility.
The file won’t attach in the first place
If the attachment button doesn’t respond or the upload stalls, first check the file size against your provider’s limit (commonly 20-25 MB). A weak connection can also cause an upload to stall indefinitely without a clear error message.
It sends, but the recipient can’t open it
This is often a file compatibility issue rather than a delivery issue — confirm the recipient has software capable of opening that file type. If you sent a link (as happens automatically with large-file tools like JumboMail or Google Drive prompts), also confirm the sharing permissions actually allow “anyone with the link,” not just people in your own organization.
The file type is being blocked
Executable files and certain script formats are commonly blocked by mail servers as a security measure. Compressing the file into a standard .zip archive often resolves this, since .zip is rarely blocked outright.
Fixing a large-file problem
If the file is simply too big, the fix isn’t to keep retrying the same attachment — switch to a cloud-link method instead. See our guide on sending large videos by email or Libero Mail’s automated JumboMail feature for two different approaches to the same problem.
Frequently asked questions
Why does my attachment upload stall without an error message?
This is often a weak connection issue rather than a limit being hit; try switching networks or waiting a moment and retrying.
Why can’t the recipient open a file I sent successfully?
Usually either a software compatibility issue on their end, or, for link-based large files, a sharing-permission setting that’s too restrictive.
Is it always safe to zip a file to avoid a blocked file-type filter?
Only if the underlying file itself is safe. Zipping doesn’t make an unsafe file safe — it may just bypass an automatic filter.