SpaceDesk HTML5 Viewer Not Working? Here’s How to Fix it

So, you finally set up SpaceDesk, excited to turn your tablet, phone, or spare laptop into a second monitor. You open the HTML5 Viewer in your browser… and it just won’t connect. Or maybe it connects, but the screen is frozen, it lags like molasses, or the browser keeps yelling “Connection Failed!” Don’t worry—you’re not alone. Let’s fix it in no time, with zero tech degree needed.

TLDR: Quick Summary

If SpaceDesk HTML5 Viewer isn’t working, first check your Wi-Fi and make sure both devices are on the same network. Try updating your browser, and ensure your firewall doesn’t block SpaceDesk. Restart both devices if needed. If all else fails, try the Desktop Viewer app instead of the browser version.

What is SpaceDesk?

SpaceDesk lets you turn another device—like a tablet or phone—into a second screen for your Windows PC. The HTML5 Viewer is the version you use right in the browser. No downloads required. It sounds super convenient, and it is… when it works!

So, if it’s acting up, let’s run through the fixes step-by-step.

1. Double-check: Are Both Devices on the Same Wi-Fi?

SpaceDesk needs your primary PC and your second device (tablet, phone, etc.) to be on the same local network. This is rule number one and the most common issue.

• Make sure both devices are on the same Wi-Fi network.
• Check that your PC isn’t using Ethernet and your tablet Wi-Fi from a different modem/router.
• If you’re using a public network, hotspot, or VPN, try switching to a private home network.

If they’re on different networks, they simply can’t talk to each other.

2. No IP, No Party

The HTML5 Viewer asks for your PC’s IP address. If you enter the wrong one—you guessed it—it won’t work.

Here’s how to find your IP address on Windows:

1. Press Windows + R
2. Type cmd and hit enter
3. In the black window, type ipconfig and press enter
4. Look for IPv4 Address (e.g., 192.168.1.145)

Enter that number into the HTML5 Viewer. No typos allowed!

3. Try a Different Browser

Some browsers don’t play nice with SpaceDesk. If you’re using an older browser or one packed with privacy features, the viewer might not load at all.

Use one of these browsers for best results:

• Google Chrome
• Mozilla Firefox
• Microsoft Edge

Pro tip: Avoid Safari! It often runs into compatibility issues with SpaceDesk.

4. Refresh, Restart, Repeat

If all else fails, try the golden oldies:

• Restart your PC
• Restart your tablet/phone
• Refresh your browser tab

You’d be surprised how many times this actually solves the issue. It’s the tech version of a deep breath and a coffee break.

5. Firewalls and Antivirus May Be the Villains

SpaceDesk uses your local network to stream your PC’s screen to your other device. If your firewall or antivirus is in the way, the connection may fail.

Here’s what to check:

• Windows Firewall: Go to Control Panel → System and Security → Allow an app through Windows Firewall
• Make sure SpaceDeskService is allowed through both Private and Public networks
• Temporarily disable any third-party antivirus software to test it out

Important: Always turn antivirus protection back on after testing!

6. Update Everything

Old software can break things. Make sure all systems are go:

• Update your browser to the latest version
• Update SpaceDesk on your host PC (the one with Windows)
• If using Windows 10 or 11, check for system updates too

Sometimes the tiniest update can fix major bugs.

7. Switch to Desktop Viewer (if nothing works)

Still no luck? Consider ditching the browser and using the SpaceDesk Viewer app instead of the HTML5 version.

• Available on iOS, Android, and Windows 10+
• Much smoother and more stable than the browser version
• Even supports touch, stylus input, and better screen resolutions

It’s free and only takes a minute to install from your app store.

8. Clear Browser Cache (Because Why Not?)

Caching is your browser’s way of remembering stuff—but sometimes it remembers the wrong things.

Clearing the cache can often fix weird behaviors:

1. Go to your browser settings
2. Search for “Clear browsing data”
3. Choose only Cached images and files
4. Click Clear
5. Restart your browser and try SpaceDesk again

P.S. This helps with other websites acting weird too. Bonus!

9. Check Permissions (for mobile devices)

Using a phone or tablet? Make sure your browser has permission to access the network. On iOS or Android:

• Go to system settings → apps → your browser
• Allow permissions like Network access or Local network

Some mobile devices block access by default.

10. Check SpaceDesk Settings

On your Windows PC, open the SpaceDesk Server. Make sure everything is active:

• Status: Server ON
• Remote Display: Enabled
• HTML5 Viewer Enabled (if applicable)

If it’s off or paused, your other device has no chance of connecting.

Let’s Recap – The Quick Fix Checklist

If your SpaceDesk HTML5 Viewer is still being difficult, run through this checklist:

• ✅ Both devices on same network
• ✅ Correct IP address entered
• ✅ Try Chrome, Firefox, or Edge
• ✅ Restarted both devices
• ✅ Checked firewalls and antivirus
• ✅ Updated browser and SpaceDesk
• ✅ Cleared browser cache
• ✅ Browser permissions OK
• ✅ SpaceDesk Server settings correct

Final Thoughts

SpaceDesk is a powerful tool when it works. When it doesn’t, it’s usually something simple—like a wrong IP or sneaky firewall. Use the steps above and you’ll be back to dual-screen bliss in no time.

And remember: If you don’t feel like troubleshooting anymore, just download the full Viewer App. Boom. Problem solved.

Happy multitasking!