--- title: Troubleshooting Server Connection Errors description: This article goes over how to --- [Skip to content](https://support.sierrabio.com/troubleshooting-server-connection-errors#main-content) English Show submenu for translations ![](https://support.sierrabio.com/hs-fs/hubfs/JPG%20file%20-02.jpg?width=2000&height=1125&name=JPG%20file%20-02.jpg) Open main navigation Close main navigation - English Show submenu for translations - [Contact us](mailto:support@sierrabio.com) [Contact us](mailto:support@sierrabio.com) How can we help you? - There are no suggestions because the search field is empty. 1. [Sierra Biosystems Support Center](https://support.sierrabio.com/?hsLang=en) 2. [Troubleshooting & Errors](https://support.sierrabio.com/troubleshooting-errors?hsLang=en) 3. [Software Errors & Communication Issues](https://support.sierrabio.com/troubleshooting-errors?hsLang=en#software-errors-communication-issues) August 1, 2025 # Troubleshooting Server Connection Errors If your KA Labs or Shasta software won’t connect to the internal database (NexusDB Server), you’ll likely see a startup error or the control panel light will stay red. This article walks you through the most common ways to resolve those connection problems. ![](https://support.sierrabio.com/hs-fs/hubfs/image-png-Jul-28-2025-05-27-29-6156-PM.png?width=367&height=149&name=image-png-Jul-28-2025-05-27-29-6156-PM.png) --- #### 🧯 Common Symptoms - KA\_Labs or Shasta Software won’t launch or gets stuck on startup - "Unable to connect to server" message - Red light in the KA\_Labs software control panel - You recently installed the software on a new PC --- #### 🛠️ Step-by-Step Troubleshooting ### 🔍 Step 1: Check the NexusDB Server Service 1. On your keyboard, press `Windows + R`, type `services.msc`, and press **Enter** ![](https://support.sierrabio.com/hs-fs/hubfs/image-png-Jul-28-2025-05-27-42-5152-PM.png?width=518&height=381&name=image-png-Jul-28-2025-05-27-42-5152-PM.png) 2. In the **Services** window, scroll to find **NexusDB Server V3** ![](https://support.sierrabio.com/hs-fs/hubfs/image-png-Jul-28-2025-05-27-52-3378-PM.png?width=526&height=387&name=image-png-Jul-28-2025-05-27-52-3378-PM.png) 3. Check the **Status** column: - If blank, right-click and select **Start** ![](https://support.sierrabio.com/hs-fs/hubfs/image-png-Jul-28-2025-05-28-07-8178-PM.png?width=406&height=314&name=image-png-Jul-28-2025-05-28-07-8178-PM.png) - If already running, continue to the next step ![](https://support.sierrabio.com/hs-fs/hubfs/image-png-Jul-28-2025-05-29-09-2295-PM.png?width=404&height=208&name=image-png-Jul-28-2025-05-29-09-2295-PM.png) 4. Try launching KA\_Labs or Shasta again --- ### 🧹 Step 2: Reset the NexusDB Folder (If Step 1 Fails) If the NexusDB server still doesn’t work: 1. Go back to the **Services** window 2. Right-click **NexusDB Server V3** \> click **Stop** 3. Open **File Explorer** 4. Go to: `C:\ProgramData\` > 🧼 *Note: This is a hidden folder. Enable “Hidden Items” in the **View** tab to access it.*![](https://support.sierrabio.com/hs-fs/hubfs/image-png-Jul-28-2025-05-30-53-4520-PM.png?width=447&height=359&name=image-png-Jul-28-2025-05-30-53-4520-PM.png) 1. Locate and **delete the folder** called: `NexusDB3` 2. Go back to the Services window 3. Right-click **NexusDB Server V3** \> click **Start![](https://support.sierrabio.com/hs-fs/hubfs/image-png-Jul-28-2025-05-31-49-1742-PM.png?width=407&height=315&name=image-png-Jul-28-2025-05-31-49-1742-PM.png)** 4. Relaunch KA\_Labs software ✅ If successful, you should now see a **green light** in the control panel. --- #### 🧩 Still Not Working? - Double-check your database settings in KA\_Labs: - IP Address: `127.0.0.1` - Hostname: (leave blank) - Location: **LAN / WAN** - Confirm your firewall or antivirus isn’t blocking KA\_Labs or NexusDB - Restart your computer and try again - [Pre-Installation & Installation](https://support.sierrabio.com/pre-installation-installation?hsLang=en#main-content) - [Pre-Installation Requirements](https://support.sierrabio.com/pre-installation-installation?hsLang=en#pre-installation-requirements) - [Site & Lab Preparation](https://support.sierrabio.com/pre-installation-installation?hsLang=en#site-lab-preparation) - [Installation & Initial Setup](https://support.sierrabio.com/pre-installation-installation?hsLang=en#installation-initial-setup) - [Troubleshooting & Errors](https://support.sierrabio.com/troubleshooting-errors?hsLang=en#main-content) - [Software Errors & Communication Issues](https://support.sierrabio.com/troubleshooting-errors?hsLang=en#software-errors-communication-issues) - [Chemistry and Protocol-Related Issues](https://support.sierrabio.com/troubleshooting-errors?hsLang=en#chemistry-and-protocol-related-issues) - [K&A - Preventative Maintenance & Quick Fixes](https://support.sierrabio.com/troubleshooting-errors?hsLang=en#ka-preventative-maintenance-quick-fixes) - [Shasta - Preventative Maintenance & Quick Fixes](https://support.sierrabio.com/troubleshooting-errors?hsLang=en#shasta-preventative-maintenance-quick-fixes) - [Shasta - Hardware Issues](https://support.sierrabio.com/troubleshooting-errors?hsLang=en#shasta-hardware-issues) - [Training Videos and Guides](https://support.sierrabio.com/training-videos-and-guides?hsLang=en#main-content) - [Shasta Software](https://support.sierrabio.com/training-videos-and-guides?hsLang=en#shasta-software) - [K&A Next Gen Software](https://support.sierrabio.com/training-videos-and-guides?hsLang=en#ka-next-gen-software) - [K&A Legacy Software](https://support.sierrabio.com/training-videos-and-guides?hsLang=en#ka-legacy-software) - [K&A - Troubleshooting Videos](https://support.sierrabio.com/training-videos-and-guides?hsLang=en#ka-troubleshooting-videos) - [Shasta - Troubleshooting Videos](https://support.sierrabio.com/training-videos-and-guides?hsLang=en#shasta-troubleshooting-videos) - [Software Updates & Release Notes](https://support.sierrabio.com/software-updates-release-notes?hsLang=en#main-content) - [Release Notes](https://support.sierrabio.com/software-updates-release-notes?hsLang=en#release-notes) - [Downloads](https://support.sierrabio.com/software-updates-release-notes?hsLang=en#downloads) - [Update Instructions](https://support.sierrabio.com/software-updates-release-notes?hsLang=en#update-instructions) - [Product Documentation & Policies](https://support.sierrabio.com/product-documentation-policies?hsLang=en#main-content) - [Technical Documentation](https://support.sierrabio.com/product-documentation-policies?hsLang=en#technical-documentation) - [Specifications](https://support.sierrabio.com/product-documentation-policies?hsLang=en#specifications) - [Warranty & Service](https://support.sierrabio.com/product-documentation-policies?hsLang=en#warranty-service) - [Oligonucleotide Chemistry & Methods](https://support.sierrabio.com/oligonucleotide-chemistry-methods?hsLang=en#main-content) - [Synthesis & Strategy](https://support.sierrabio.com/oligonucleotide-chemistry-methods?hsLang=en#synthesis-strategy) - [Post-Synthesis Processing](https://support.sierrabio.com/oligonucleotide-chemistry-methods?hsLang=en#post-synthesis-processing) - [Quantitation & QC](https://support.sierrabio.com/oligonucleotide-chemistry-methods?hsLang=en#quantitation-qc) - [Special Topics](https://support.sierrabio.com/oligonucleotide-chemistry-methods?hsLang=en#special-topics) - [Support & Contact](https://support.sierrabio.com/support-contact?hsLang=en) - [Uncategorized](https://support.sierrabio.com/uncategorized?hsLang=en) [![](https://support.sierrabio.com/hs-fs/hubfs/JPG%20file%20-02.jpg?width=2000&height=1125&name=JPG%20file%20-02.jpg)](http://sierrabio.com) [mailto:Support@sierrabio.com](mailto:Support@sierrabio.com) Copyright © 2025, Sierra BioSystems