Online Installation:
If the Real-Time(RT) target has internet access, make sure it can connect to download.ni.com. To check this:

1. Set up an SSH connection to the RT target from the host PC
2. Use the following command to ping the NI feed site:  ping download.ni.com.
3. If the connection is successful, you should get replies as shown below. If not, continue with other troubleshooting below or try the offline feed method below.

Offline Installation:

• To perform an offline installation to the target, follow these steps Installing Software to Offline NI Linux Real-Time Targets. You’ll need to make sure that both NI Linux Real-Time Offline Installation Support and NI System Configuration are installed in the host computer first.
• Verify the connection between the RT controller and the host PC through a ping command to the IP of your target.
  • Open the Command Prompt in Windows and run the following command: ping <Linux RT IP Address>.
• Set up an SSH connection in the RT target and make sure you can ping the host PC back: ping <Host PC IP Address>.

General troubleshooting:

• If your Real-Time (RT) controller is brand new, ensure that you have installed an NI Linux RT System Image on your host PC. 
• In case you added online feeds manually, check if these feeds are correctly spelled, do not contain any spaces, and that you can access them from a web browser. If the feeds added are not required, try deleting the faulty feeds mentioned in the error message.

• If this is a PXIe system that you recently migrated from PharLap, make sure its BIOS is updated to the latest version. Download the latest BIOS version from the website and follow the instructions in the downloaded files to proceed with the update. For instance, here is the link for the PXIe-8880 controller: PXIe-8880 Firmware and Additional Drivers Download.

• When the offline installation process is required, make sure that the connection is not being blocked by the computer’s local firewall or antivirus. Confirm with your IT team that the port used during the installation process is opened. Please check the following article for instructions on how to configure the network firewalls correctly, so they can support NI software: Configuring Software and Hardware Firewalls to Support NI Products.

• It’s suggested to temporarily turn off the Windows firewall to try to access the download server for the packages being requested. You can use the Troubleshoot Remote System Discovery tool (NI MAX>>right-click over Remote Systems) to confirm no firewall or antivirus is blocking the connection. Note: It is important to consider this tool as a quick test and not as a conclusion. Even if the tool does not show any restrictions, you can still be blocked by some company restrictions (firewall, antivirus, network, local settings, etc...).

• Make sure that the NI RT Feed Host Configuration software is allowed to make changes to your computer. If you are not sure if it has the correct permissions, please follow the steps below:

1. Open Command Prompt as administrator on your PC.
2. Run the netsh advfirewall reset command, as shown in the image below. This will reset your firewall to its default configuration. 

3. Go to NI MAX and retry adding software to your RT controller. A window asking for your permission to allow the NI RT Feed Host Configuration software to make changes on your PC may pop up. Click on the Yes button to allow access. Review the following picture for more information. 

• If your computer uses a network proxy, make sure that there is an exception made for download.ni.com, please follow the steps in this article in order to do so.