QNAP NAS Error Code 37: How to Fix It

Medium 15-30 minutes Medium Severity Verified June 2026
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Error Code
37
Brand
QNAP
Product Type
nas
Severity
Medium
DIY Difficulty
Medium
Estimated Fix Time
15-30 minutes
QNAP NAS Error Code 37 indicates that the SSL certificate installed on your device has expired, which prevents secure HTTPS connections to the NAS management interface. This error is a medium-severity issue — your NAS is still functional and your data is safe, but browser security warnings will block access and encrypted remote connections may fail. Renewing or replacing the SSL certificate will fully resolve this error without any hardware changes.
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Tools You'll Need

How to Fix Error Code 37

  1. Access the QNAP Management Interface

    Do not use an untrusted public network to perform this procedure. Only connect from a secure, private local network to avoid exposing credentials during an unencrypted HTTP session.

  2. Navigate to the SSL Certificate Settings

  3. Renew a Let's Encrypt Certificate (Recommended for Most Users)

    Port 80 must be temporarily forwarded on your router to your NAS for Let's Encrypt domain verification to succeed. After the certificate is issued, you may close port 80 again if not needed.

  4. Upload a Third-Party SSL Certificate (Advanced Users)

    Keep your private key file secure. Never share it or store it in a publicly accessible location. Back up the key file to a safe offline location before uploading.

  5. Generate a New Self-Signed Certificate (Offline NAS or No Domain)

  6. Restart Web Server and Verify the Fix

  7. Enable Automatic Certificate Renewal

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When to Call a Professional

Contact QNAP technical support or a qualified IT professional if: you are unable to log in to the QTS management interface at all; the certificate replacement process repeatedly fails with an error other than Code 37; you manage a business-critical NAS with strict compliance requirements (such as PCI-DSS or HIPAA) where certificate management must follow a formal process; or if your NAS is part of an enterprise network managed by an IT department that controls certificate infrastructure. QNAP offers paid support plans and live chat via their official support portal.

Frequently Asked Questions

Is my data at risk when QNAP Error Code 37 appears?
No, Error Code 37 does not affect your stored data in any way. It only means the SSL certificate used for encrypted HTTPS connections has expired. Your files remain intact and the NAS continues operating normally. The error simply prevents secure browser connections until the certificate is renewed.
Can I still access my QNAP NAS while the SSL certificate is expired?
Yes. You can access the management interface by using the HTTP address (e.g., http://192.168.1.100:8080) on your local network, which bypasses the SSL requirement. Some browsers also allow you to click 'Advanced' and proceed past the certificate warning for HTTPS connections, though this is not recommended as a permanent solution.
How often does a Let's Encrypt certificate on QNAP expire?
Let's Encrypt certificates are valid for 90 days. With QNAP's automatic renewal feature enabled, QTS will renew the certificate automatically before expiry. If auto-renewal is not enabled, you will need to manually renew it every 90 days to avoid Error Code 37 returning.
Why does my browser still show a security warning after I updated the QNAP SSL certificate?
This is usually caused by a cached version of the old certificate in your browser. Clear your browser cache and cookies (Ctrl+Shift+Delete), then close and reopen the browser before visiting the QNAP interface again. Also restart the QNAP Web Server service in the Control Panel to ensure the new certificate is fully loaded.
Do I need a domain name to fix QNAP Error Code 37?
A domain name is only required if you choose to use a Let's Encrypt certificate, as Let's Encrypt verifies ownership of a public domain. If your NAS is only accessed locally or you do not have a domain, you can generate a free self-signed certificate instead. The self-signed option will still trigger browser 'not trusted' warnings, but it will resolve Error Code 37 and restore encrypted HTTPS connectivity.

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