> ## Documentation Index
> Fetch the complete documentation index at: https://docs.ntop.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Why is the desktop app unable to connect to nTop's license server?

## Issue:

After installing, changing passwords, or logging out, a sign-in prompt will display when starting the software. Some users may encounter the message:

`Unable to connect to nTop's license server. Please contact your IT department
 and have them review the Licensing Quick Start Guide above.`

## Applies to:

* nTop
* Cloud Licensing

## Cause:

There are a few reasons the login screen may display this error message.

* Security settings are blocking the software from contacting our database.
* An unstable internet connection is preventing the software from communicating with us.

## Solution:

The user's organization may need to allowlist nTop servers or adjust security settings. Please review the following articles for assistance:

* [nTop System Requirements Guide](/help-articles/access-and-installation/system-requirements/system-requirements-guide)
* [nTop Cloud Licensing Access Guide](/help-articles/access-and-installation/accounts-and-licensing/ntop-allowlisting-guide)
* [nTop Cloud Licensing Proxy Settings Guide](/help-articles/access-and-installation/accounts-and-licensing/ntop-proxy-settings-guide)

If the issue persists, we may need to connect with your IT department to fix the problem.

## Keywords:

*licensing error cloud account app server issue whitelisting unable*