Login failure (OAuth callback broken) on macOS – localhost connection reset

[Leonardomachad0]

Before opening, please confirm:

• I have searched for duplicate or closed issues

Operating System

macOS

Kiro Version

0.11.34

Bug Description

Hi,

I'm experiencing a persistent login issue with Kiro IDE on macOS.

The authentication flow starts normally:

• I select login (Google / GitHub / any provider)
• Browser opens successfully
• Authentication completes on the provider side

However, the redirect back to localhost fails:

http://localhost:3128/oauth/callback

Error:

• "Connection reset by peer"
• Browser cannot load the localhost callback page

---

What I tested

• Different browsers (Safari, Chrome)
• Different login methods (Google, GitHub)
• CLI install (kiro-cli) → same issue
• DNS changed to Cloudflare (1.1.1.1)
• Cleared DNS cache
• Modified /etc/hosts to prioritize IPv4 (127.0.0.1)
• Disabled IPv6 (::1 localhost removed)
• Verified port 3128 is open:
  lsof -i :3128 → Kiro is listening
• Tested with curl:
  curl http://127.0.0.1:3128 → connection reset

---

System info

• macOS (MacBook Air)
• Shell: zsh
• No VPN active
• Stable internet connection
• Location: Brazil

---

Observation

The issue seems to be that:

• Kiro opens the local server
• but immediately closes the connection during OAuth callback

This makes login impossible via both UI and CLI.

---

Request

Could you please confirm if:

• there is any known issue with OAuth callback handling on macOS?
• or if additional configuration is required?

Thanks!

Steps to Reproduce

1. Open Kiro IDE on macOS
2. Click "Sign In"
3. Browser opens and authentication completes (Google/GitHub)
4. Redirect to http://localhost:3128/oauth/callback
5. Browser fails to load the page with connection error
6. Kiro does not complete login

Expected Behavior

After successful authentication in the browser, Kiro should receive the OAuth callback and complete the login automatically.

Conversation ID

No response

Additional Context

• Tested multiple browsers (Safari, Chrome)
• Tested multiple login providers (Google, GitHub)
• DNS changed to Cloudflare
• IPv6 disabled
• Port 3128 is open but connection resets
• CLI login also fails

This appears to be an issue with the local OAuth callback server.

[github-actions]

🤖 Potential Duplicate Detected

This issue appears to be similar to:

• #6255: Cannot login via CLI (85% similar)
• #5810: Streamline re-authentication flow when login tokens expire for Enterprise IAM Identity Center customers. (85% similar)
• #5475: Login issues when switching between IdC and Social sign ins (85% similar)
• #4820: Pop up login/register after SSH connectis still stuck not moving (85% similar)
• #4681: can't login kiro (85% similar)
• #4550: kiro-cli无法完成您的请求，请稍后重试，导致我无法登录使用kiro cli (85% similar)
• #4333: Better Sign In Experience and Session Management for Kiro CLI (85% similar)

What happens next?

• ⏰ This issue will be automatically closed in 3 days
• 🏷️ If this is not a duplicate, you can prevent automatic closure by adding a comment or reacting with 👎 to this message.
• 💬 Comment on the original issue if you have additional information

Why is this marked as duplicate?
Both report OAuth login failures on macOS with localhost callback issues - same core authentication problem

[Leonardomachad0]

I'm still experiencing the issue.

I tested:

• DNS change
• IPv6 disabled
• localhost forced to IPv4
• port 3128 is open
• curl returns connection reset

The problem persists and prevents login completely.

This seems to be a blocking issue, not just a duplicate.

[github-actions]

Thank you for your feedback! 🙏

The duplicate label has been removed and this issue has been sent back for maintainer review.

A maintainer will review this issue shortly.

[AnilMaktala]

Hey @Leonardomachad0, thanks for the detailed report and thorough troubleshooting — really appreciate you documenting everything you've already tried.

A few questions to help us narrow this down:

• Firewall / security software — Are you running any firewall or antivirus software that might be intercepting or resetting local connections?

• Port conflict — Even though lsof -i :3128 shows Kiro listening, could you try: lsof -i :3128 -P -n
  to confirm there isn't another process competing for that port?

Kiro logs — Could you share the relevant logs from the Kiro IDE?

Network proxy — Even without a VPN, is there any system-level proxy configured? You can check under System Settings > Network > Wi-Fi > Details > Proxies.

[Leonardomachad0]

Hi, thanks for the follow-up and for the detailed troubleshooting steps.

Here are my findings:

1. Firewall / security

• macOS firewall is OFF
• No third-party firewall or antivirus installed

2. Proxy

• No system proxy configured (all proxy options are disabled)

3. Port check
   Running:
   lsof -i :3128 -P -n

consistently shows:

Kiro H ... TCP 127.0.0.1:3128 (LISTEN)

I ran this multiple times and always get the same result, so Kiro is stably listening on 127.0.0.1:3128 and there does not appear to be any port conflict.

4. Local connectivity test
   Running:
   curl -v http://127.0.0.1:3128

results in:

• Successfully connects to 127.0.0.1:3128
• Request is sent
• Then: "Recv failure: Connection reset by peer"

So the Kiro local server accepts the connection but immediately resets it instead of returning a valid HTTP response.

5. Observed behavior
   During login, the browser redirects to:
   http://localhost:3128/oauth/callback

but fails with:
ERR_CONNECTION_RESET

6. Conclusion
   At this point, it does not appear to be a firewall, proxy, DNS, or port binding issue.

Kiro is successfully binding to localhost:3128, but the local OAuth callback server seems to be resetting incoming connections instead of handling them properly.

7. Additional context

• Location: Brazil
• Tested on different networks (Wi-Fi and mobile hotspot)
• Same behavior in all cases

Please let me know if you would like specific log files. I found logs under:
~/Library/Application Support/Kiro/logs/