Fix 404 DEPLOYMENT_NOT_FOUND Error (Vercel + Hashnode + Cloudflare)

If you're seeing the “404: DEPLOYMENT_NOT_FOUND” error on your website or subdomain, especially when using Vercel, Hashnode, and Cloudflare, you're not alone.

This is a common but confusing issue where your domain suddenly stops working even when everything looks correctly configured.

In this guide, I’ll show you the real cause and a 100% working fix.

What is “DEPLOYMENT_NOT_FOUND” Error?

This error usually looks like:

404: NOT_FOUND
Code: DEPLOYMENT_NOT_FOUND

It means: Your domain is pointing to Vercel But Vercel cannot find a valid deployment

💥 Root Causes:

• Old Vercel routing still cached

• Domain mapping mismatch

• Hashnode internal deployment sync issue

• Removing one domain breaks others (critical bug)

⚠️ Common Scenario (Important)

You have multiple subdomains like:

• blog.yoursite.com

• seo.yoursite.com

• uiux.yoursite.com

👉 When you remove any one of these domain from Hashnode:

❌ Other domains may also start showing:
DEPLOYMENT_NOT_FOUND

✅ 100% Working Solution (Tested Fix)

Follow these steps carefully:

🔧 Step 1: Remove ALL Custom Domains

Go to Hashnode → Blog Settings → Domains

👉 Remove ALL subdomains of your single or multiple blogs first and remember that which blog has which domain name:

• blog.yoursite.com

• seo.yoursite.com

• uiux.yoursite.com

• etc

🔧 Step 2: Wait 2–5 Minutes

Let the system clear old mappings. Ctr+Shift+R for hard reload.

🔧 Step 3: Re-add All Domains

Now reassign each domain one by one. Ensure that all domains are removed first before reassigning them; otherwise, proper mapping may not occur.

blog.yoursite.com
seo.yoursite.com
uiux.yoursite.com

🔧 Step 4: Verify DNS (Cloudflare or your DNS server)

Make sure:

• Type: CNAME

• Value: hashnode.network

• Proxy: DNS only (important)

🔧 Step 5: Clear Cache

• Cloudflare → Cache → Purge Cache → Everything

• Browser → Hard refresh (Ctrl+Shift+R)/ Incognito

Final Result

✔ All subdomains start working
✔ 404 error disappears
✔ Hashnode reconnects properly

👉 Never remove only ONE domain in a multi-subdomain setup, Instead:

✔ Remove all → then → Reconnect all

Conclusion

The DEPLOYMENT_NOT_FOUND error is not always a DNS issue, it’s often a routing sync problem between Vercel and Hashnode.