Troubleshooting guide

Send to Kindle Not Working: 7 Fixes (and a Backup That Always Works)

If Send to Kindle isn't working, the most common causes are email-approval-list misconfiguration, file size limits, and Amazon's intermittent server issues — but if Amazon's native flow keeps failing, leafbind converts PDFs to KFX you can sideload directly, bypassing Send to Kindle entirely.

By Joe Fowler — Updated May 17, 2026

What's not working?

Send to Kindle failures fall into four categories. Identify yours first — the fixes are different.

Email not arriving on Kindle

You sent the file but it never appeared in your library. Almost always an approved sender issue (Fix #1) or delivery delay (Fix #4).

File rejected at send time

You got a bounce email from Amazon or the app showed an error. Check file size (Fix #2) and format (Fix #3).

App crashing or not responding

The Send to Kindle desktop extension or mobile app is failing before sending. See Fix #6 for app-specific steps.

File arrives but looks wrong

Text is garbled, columns are merged, or footnotes are missing. Amazon converts PDFs in ways that break academic and technical documents — see the backup option at the end of this guide.

Fix #1: Check your approved sender list

This is the most common cause of Send to Kindle failures. Amazon's service only delivers personal documents from email addresses you have explicitly approved. If you send from a new address, a work email, or any address not on the list, Amazon silently drops the message — no bounce email, no notification on the device.

To add your sending address to the approved list:

Go to amazon.com/mycd (Manage Your Content and Devices)
Click Preferences
Scroll to Personal Document Settings
Under Approved Personal Document E-mail List, click Add a new approved e-mail address
Enter the exact address you send from and save

After adding the address, resend the file. Amazon does not retroactively deliver messages that were blocked before you added the address.

Fix #2: Check file size limits

Amazon's Send to Kindle web uploader accepts files up to 200 MB. The email method historically capped attachments at 50 MB; Amazon's current email documentation no longer explicitly states this limit. USB cable transfers have no size restriction.

If your file is too large, you have two options:

Use the web uploader. Go to amazon.com/sendtokindle and upload the file directly — the 200 MB limit covers most PDFs.
Transfer via USB. Connect your Kindle with a USB cable, open the device in File Explorer, and copy the file into the Documents folder. No size limit applies to USB transfers.

Fix #3: Verify the file format

Send to Kindle accepts a specific set of file formats. If you are sending a format not on this list, Amazon will reject it:

PDF
DOC, DOCX (Microsoft Word)
RTF
TXT
HTML, HTM
EPUB (DRM-free only)
PNG, GIF, JPG, JPEG, BMP (images)

Formats no longer accepted: MOBI — Amazon removed MOBI support in 2022. If you have a .mobi file, open it in Calibre and export to EPUB or PDF before sending.

Formats commonly confused as supported but not accepted: CBZ (comic archives), ODT (LibreOffice), Pages (Apple), AZW3 (Kindle store books with DRM), and DRM-protected EPUB3 files. If your file is in an unsupported format, convert it to PDF first.

Fix #4: Check email delivery delays

Amazon documents that Send to Kindle delivery can take up to 15 minutes. If you sent a file recently and it has not appeared, wait before assuming something is broken.

One common mistake: checking only the physical Kindle device rather than your Amazon library. Device sync can lag behind server-side delivery. Check your library at amazon.com/mycd — if the file appears there but not on your device, the issue is device sync rather than delivery failure. Force a sync by going to your Kindle's home screen and pulling down to refresh, or toggling Wi-Fi off and back on.

Fix #5: Check Amazon's service status

Amazon's Send to Kindle service occasionally has outages or degraded performance that affect delivery. If you have verified your approved sender list and file format, and files are still not arriving after 15+ minutes, Amazon's service may be experiencing issues.

Check Amazon's customer service help page and look for any notices about personal document delivery. You can also check third-party services like Downdetector or search recent Reddit posts in r/kindle — widespread issues typically surface there quickly. If Amazon is having a service disruption, the only option is to wait or use USB transfer in the meantime.

Fix #6: App-specific issues

iOS and Android (mobile app)

If the Send to Kindle mobile app is crashing or not sending files, force-close the app completely and reopen it. On iOS: swipe up from the bottom edge and swipe the app card away. On Android: open Recent Apps and dismiss Send to Kindle, then relaunch. If the problem persists after a force-close, check for app updates in the App Store or Google Play — Amazon periodically releases fixes for known app issues.

iOS-specific quirk: the Share Sheet extension (the Send to Kindle option in iOS's share menu) occasionally stops responding after an iOS update. If the Share Sheet entry is missing or grayed out, uninstall and reinstall the Send to Kindle app to re-register the extension.

Desktop (browser extension)

The Send to Kindle browser extension for Chrome and Edge occasionally breaks after browser updates. If the extension toolbar button is unresponsive or produces errors, remove the extension from your browser's extension settings and reinstall it from the Chrome Web Store or Microsoft Edge Add-ons page. Re-entering your Amazon account credentials after reinstall is normal.

Fix #7: Approved sender email domain

Some email providers and corporate email servers block outbound email to Amazon's kindle.com domain as a spam-prevention measure. If you are sending from a work, school, or custom domain email address, the email may be blocked before it reaches Amazon.

Test by sending from a personal Gmail or Outlook account instead. If delivery works from Gmail but not from your work address, the issue is your email provider's outbound filtering — not your Amazon settings. In that case, the practical workaround is to either send from Gmail or use USB transfer.

If you must send from your work address, contact your IT department and ask them to whitelist outbound SMTP to kindle.com.

If nothing works: the backup that always works

If you have worked through all seven fixes and Send to Kindle is still not delivering your file — or if it is delivering but the converted result is not readable — sideloading is the most reliable alternative. It bypasses Amazon's email delivery system entirely.

leafbind converts PDFs to KFX — Kindle's native format. Unlike Send to Kindle's conversion, leafbind uses coordinate-based extraction to handle multi-column layouts, preserves footnotes as tappable Kindle popups, and detects headings for a navigable table of contents. The resulting KFX file can be transferred directly to any Kindle device released since 2018 via USB — no email involved.

The process: upload your PDF at leafbind.io/convert/pdf-to-kfx, download the KFX file, connect your Kindle via USB, and copy the file into the Documents folder. The file appears in your library immediately. No Amazon account settings required, no email approval list, no 50 MB limit for the sideload step itself.

Free tier: EPUB output, up to 20 MB, 3 conversions per day, no account required. KFX output (with column detection, footnote linking, and heading classification) is available on premium plans. See conversion options →

Frequently asked questions

How do I find my Kindle's Send to Kindle email address?

On your Kindle device, go to Settings → Your Account → Send-to-Kindle. Your personal document email address is listed there — it ends in @kindle.com. You can also find it at amazon.com → Account → Manage Your Content and Devices → Preferences → Personal Document Settings.

What is the file size limit for Send to Kindle?

The Send to Kindle web uploader (amazon.com/sendtokindle) accepts files up to 200 MB. The email method historically imposed a 50 MB limit; Amazon's current email page does not explicitly state this limit. USB cable transfers have no size limit. If your file exceeds 200 MB, use USB transfer or split the PDF.

Why does my PDF look wrong after Send to Kindle converts it?

Amazon converts PDFs to Kindle format, which flattens multi-column layouts, drops footnote links, and may misclassify headings — common problems with academic papers, research PDFs, and technical documents. For PDFs where layout fidelity matters, use leafbind instead: it converts PDF to KFX with column-aware extraction, footnote linking, and heading detection.

How do I add an approved email to Send to Kindle?

Go to amazon.com → Account → Manage Your Content and Devices → Preferences → Personal Document Settings → Approved Personal Document E-mail List → Add a new approved e-mail address. Only emails from addresses on this list will be delivered to your Kindle. This is the most common cause of Send to Kindle not working.

Does the Send to Kindle app work on iPhone?

Yes — the Send to Kindle iOS app is available on the App Store. It requires your Kindle personal document email to be configured and the sending email to be on your Approved Personal Document E-mail List. If the app isn't delivering files, force-close and reopen it, then verify your approved sender list in Amazon's account settings.

Which file formats does Send to Kindle accept?

Send to Kindle currently accepts PDF, DOC, DOCX, RTF, TXT, HTML, PNG, GIF, JPG, BMP, and EPUB (DRM-free only). MOBI is no longer accepted — Amazon removed MOBI support in 2022. For formats not on this list — such as CBZ, ODT, or Pages files — convert to PDF first, then send.

How long does Send to Kindle take to deliver a file?

Delivery is usually within a few minutes, but Amazon documents that it can take up to 15 minutes. Check your Kindle library on the Amazon website (amazon.com/mycd) rather than waiting for the file to appear on a physical device — library sync can lag behind server-side delivery.

PDF to KFX converter →How to send PDFs to Kindle →PDF to KFX for Kindle Scribe →

Sources

Amazon Send to Kindle — supported file types and web uploader (last verified 2026-05-17)
Amazon Send to Kindle for Email — step-by-step instructions (last verified 2026-05-17)

Try leafbind free

Upload a PDF and convert to EPUB at no cost — 3 conversions per day, up to 20 MB, no account required. KFX output with column detection, footnote linking, and heading classification is available on premium plans.

See pricing — plans start at a single conversion credit with no subscription required.

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Joe Fowler is a developer and technical writer who built leafbind after spending an unreasonable amount of time coaxing academic PDFs into something readable on a Kindle. He writes about PDF structure, ebook formats, and the conversion pipeline at leafbind.io.