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Home > Success Center > Customer Service > Customer Service - Knowledgebase Articles > It is not possible to connect to the licensing server

It is not possible to connect to the licensing server


It is not possible to connect to the licensing server.


All versions of License Manager


The communication with the licensing server consists of a chain of events. It starts at the licensor, which calls the runtime modules. The runtime modules call the operating system, and then the operating system sends data to the internet. The communication can be blocked at any single part of this chain. The most common communication blockers are the following:

  • Lack of internet connection
  • Lack of direct access to the internet
  • DNS related issues
  • Antivirus or firewall related issues
  • Issues with the runtime environment and the .NET framework

To troubleshoot these issues, check the following:

  • Lack of internet connection: To see whether the computer can connect to the internet, open any page in a browser. If the page is displayed, the computer is connected to the internet. If it is not displayed, contact your ISP.
  • Lack of direct access to the internet: If the network traffic goes through a proxy server, the proxy can filter the traffic and block access to the internet. A login name and password may also be necessary for accessing the internet. A browser can work without problems, but other programs can be blocked because of the proxy server settings. If you use a proxy server, make sure that you specify the proxy server parameters during the registration process.
  • DNS related issues: While data is being sent, the IP address of the server has to be resolved from its domain name. The IP address of a domain name can vary from time to time. To check whether the domain name can be resolved, run the nslookup and the nslookup commands in the command prompt. If the command does not return an IP address, the DNS server is probably unavailable. In this case, contact your ISP.
  • Both and must be available, and port 80 and 443 must be open for these addresses.
  • Antivirus or firewall related issues: Antivirus software and firewalls can block regular network traffic. The blocking level can be set for network traffic parameters, and for specific applications as well. To make sure that it is possible to communicate with the licensing server, check your antivirus and firewall settings, and then define an exception for the licensing program or the website if they are blocked. To see if there were blocked communication attempts, check the log file of your antivirus software or firewall.
  • Issues with the runtime environment and the .NET framework: The licensor uses the .NET framework. If the framework is updated or if its configuration settings are changed, it is possible that there is a corrupted module in it, or that the version is incorrect. It is also possible that the client profile version of the .NET framework does not contain all the required modules. Run the dir /a:d  %windir%\Microsoft.NET\Framework command to display the installed versions. For licensing to work, at least one of the following two versions has to be installed: v2.0.50727, v4.0.30319. If you have only installed the .NET framework v2, please consider installing the .NET framework v3.5 SP1, which is available on the following site:  (© 2016 Microsoft, available at, obtained on October 25, 2016.)


Disclaimer: Please note, any content posted herein is provided as a suggestion or recommendation to you for your internal use. This is not part of the SolarWinds software or documentation that you purchased from SolarWinds, and the information set forth herein may come from third parties. Your organization should internally review and assess to what extent, if any, such custom scripts or recommendations will be incorporated into your environment.  You elect to use third party content at your own risk, and you will be solely responsible for the incorporation of the same, if any.


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