Why isn't my file transfer email being received?

Your recipient claims they haven't received anything? In 80% of cases, the email is blocked by a security filter (Mailinblack, Microsoft Defender, Proofpoint).

Quick answer

The email isn't lost: it's in quarantine and needs to be manually approved by your recipient or their IT department.

Quick summary

Cause: Professional spam filter blocks download links

Solution: Check quarantine and personalize your message

Prevention: Use a service adapted to secure environments

Context

Your client claims they haven't received anything? In 80% of cases, the email isn't lost: it's in quarantine, blocked by a professional spam filter (Mailinblack, Microsoft Defender, Proofpoint).

This guide helps you quickly identify if the download link is blocked and resolve the reception issue.

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Quick test

Quick test (30 seconds)

Instantly identify if the professional spam filter is blocking your download link

Send a simple email without a download link

Then send the same email with the download link

If only the second one doesn't arrive → the filter is blocking the transfer

This is exactly the diagnosis users look for when facing an email blocked by Mailinblack or another email security gateway.

Diagnosis

How to identify and resolve the blockage

Follow these steps to understand why your file isn't arriving and quickly unblock the situation

Step 1 — Check if the email was blocked by a professional spam filter

Companies use email security gateways (Mailinblack, Microsoft Defender, Proofpoint…) that analyze every message before delivery.

An email containing an external download link can be automatically blocked
Links to WeTransfer, Drive, Dropbox are often filtered by professional spam filters
Automatic or too-short messages are suspicious for filter passage
Unknown sender domain triggers an alert in the security gateway

Step 2 — Confirm the message is in enterprise email quarantine

Ask the recipient to check several locations where the message may be held by the spam filter.

Check spam or junk mail folder
Check security quarantine (often accessible via a dedicated web portal)
Ask IT department to search for your sender domain in enterprise email quarantine
Very often, the email blocked by Mailinblack is present but held on the company side

Step 3 — What your recipient should do (copy-paste)

Precise instructions to send to your recipient to authorize message delivery.

Open security quarantine (web portal or application)
Authorize your sender domain in settings
Add your address to approved sender or whitelist
After authorization, next emails arrive normally without blocking

Step 4 — Test if the download link is responsible

Isolate the problem by testing with and without the download link to identify the blockage.

First send a simple text message: "Can you confirm you receive this email?"
If the text arrives, resend the same message with the download link
If text arrives but not the link → the professional spam filter blocks file transfer
You now know it's the link being blocked by the email security gateway

Step 5 — Correct the email to improve reception

Apply these best practices so your message passes professional spam filters (Mailinblack, Microsoft Defender, Proofpoint).

Add a real personalized human message to avoid enterprise email quarantine
Avoid automatic impersonal messages that trigger filters
Don't use generic addresses (contact@, noreply@) suspicious to security gateways
Prefer sending from your professional personal address to facilitate message delivery

Step 6 — Verify the file was actually received

Without confirmation, you don't know if the message was blocked, ignored, or opened.

Ask the recipient for receipt confirmation
Use a download link with tracking to avoid unnecessary follow-ups
Verify the file was downloaded before considering the send successful
Automatic receipt acknowledgment avoids misunderstandings about security blocking

Best practices

How to write an email that won't be blocked

Concrete examples to improve your email delivery

Add a real human message

Personalize your email to avoid automatic filters.

Here's the file

Hi Julie, Here are the photos from the March 15 delivery. Let me know if everything is OK.

Avoid automatic impersonal messages

Filters more easily block automatically generated emails.

Don't use a generic address

Prefer your professional personal address.

contact@ or noreply@

firstname@company.com

Be able to manually resend a link

When the first message is blocked, the most effective solution is to send the link directly via your professional messaging.

Context

When this problem occurs most often

Certain professional environments are particularly vigilant about external file transfers

Large enterprises

Reinforced security filters and strict policies

Government agencies

Maximum security for public data

Banks & Insurance

Regulatory compliance and sensitive data protection

Accounting firms

Protection of tax and confidential data

Secure IT services

Very restrictive security policies

Healthcare sector

Health data protection (strict GDPR)

The more secure the structure, the more public transfers like WeTransfer or Dropbox are filtered.

FileVert Solution

FileVert improves your email delivery

Rather than bypassing security filters, we've adapted our operation to improve reception of your download links.

Optimized email signature

Configured to be recognized as reliable by main professional messaging filters

Enriched content

Sender name in subject and body to avoid automatic blocking

Clean HTML structure

No obscure code or shortened URLs that trigger spam filters

Download confirmation

Know in real-time who received and downloaded your file to avoid unnecessary follow-ups

Copyable manual link

Get the unique link in one click to send directly via your professional messaging if needed

French hosting

100% hosted in France, no advertising, no exploitation of your transfer data

Discover FileVert

Frequently asked questions

Your questions about blocked emails

Answers to the most common questions about file transfer email blocking

Companies use security gateways (Mailinblack, Microsoft Defender, Proofpoint) that automatically block external links like WeTransfer, Drive or Dropbox. The message is often in quarantine, not lost. Ask the recipient to check their spam and security quarantine.

First send a simple text message without a link. If the text arrives but not the message with the link, the filter is blocking the file transfer. Ask the recipient to check the spam folder, security quarantine, or contact their IT department.

Large enterprises, government agencies, banks, insurance companies, accounting firms and secure IT services have very strict filters. The more secure the structure, the more public transfers (WeTransfer, Dropbox) are filtered to protect against phishing and malware.

Add a real personalized message (avoid "Here's the file"), don't use generic addresses (contact@, noreply@), prefer your professional personal address, and avoid automatic messages that are too short. A human and contextualized message passes filters much better.

FileVert has adapted its operation to professional filters: optimized email signature recognized as reliable, enriched content with sender name in subject and body, clean HTML structure without obscure code or shortened URLs, tests on different spam filters (Mailinblack, Microsoft Defender), real-time download confirmation, and copyable link for manual sending if needed.

Copy the download link and send it via another channel (direct email, SMS, professional messaging). If the problem persists, ask the recipient to contact their IT department to authorize the filevert.fr domain. FileVert also allows password protection of the link to reassure security services.

Send your files without fearing blockages

FileVert is designed to pass professional filters while guaranteeing the security of your transfers.

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