If you are unable to access your Object Storage or buckets, the most frequent cause is that the Object Storage URLs (such as eu2.contabostorage.com) have been blacklisted.

In some cases, users may upload malicious content such as viruses or phishing material to Object Storage. Although such content is detected and blocked very quickly, the associated URLs can temporarily end up on public or local blacklists.

When this happens, you may see the following error message in your Customer Control Panel:

“We were unable to perform the request. You are most likely being affected by blacklisting.”

To resolve this issue, please ensure that the Object Storage URLs are not blacklisted in your:

• Internet security software (Antivirus/Firewall)

• (Home) router

• Browser

To see if your URLs are blacklisted, check the following:

1. Internet Security Software (Antivirus/Firewall)

Open your antivirus software and check the following sections:

• Blocked URLs

• Web Protection

• Firewall settings

Search for entries such as:

• eu2.contabostorage.com

• *.contabostorage.com
  
  

If the domain is listed, remove the block or add it to the allowlist / exceptions list.

If you are unsure whether your security software is causing the issue, you may temporarily disable web protection for testing purposes. If access works afterward, the domain needs to be allowlisted.

2. Home Router

Log in to your router’s administration interface and check:

• Parental controls

• DNS filtering

• Content filtering

• Firewall rules
  
  

Ensure that *.contabostorage.com is not blocked.

If you are using a custom DNS service, verify that the domain is not filtered there.

3. Browser

Check your browser for:

• Security or privacy extensions

• Ad blockers

• Built-in security features

To test:

• Open the Object Storage URL in a private/incognito window.

• Try a different browser.

• Temporarily disable browser extensions.
  
  

If it works in another browser or in incognito mode, a browser extension is likely causing the block.

How to reduce the risk of blacklisting

Blacklisting is usually temporary and may be caused by activity unrelated to your account, as Object Storage endpoints are shared infrastructure. However, you can help reduce the risk by:

• Not hosting or distributing malware or phishing content

• Securing your Object Storage credentials to prevent misuse

• Scanning files for viruses before uploading or distributing them publicly
  
  

In most cases, blacklist entries are temporary and are automatically removed after review.