Error Troubleshooting

Error Message - Failed to load resource: net::ERR_CERT_DATE_INVALID

Symptom

You get an error message that says “Failed to load resource: net::ERR_CERT_DATE_INVALID https://local.dynamsoft.com:18623/f/VersionInfo?ts=XXXXXXXXXXXX”. And the browser keeps asking to install the Dynamic Web TWAIN Service (previously called “Dynamsoft Service”).

Cause

By default, “127.0.0.1” is used for service connection. “127.0.0.1” uses a self-signed SSL certificate without an expiry date. It is installed to your system so that the browser can trust it. If your environment requires high level security, self-signed certificates may not be accepted. Moreover, it is not easy to install the self-signed certificate for systems like Chrome OS.

In this case, we provide a domain, “local.dynamsoft.com”, which points to “127.0.0.1”. It has a VeriSign’ed certificate that has an expiry date. The most recent expired “local.dynamsoft.com” certificate expired on 2025 November 20th, and the latest certificate will expire on 2026 November 21st.

Please note: all official certificates issued by 3rd party come with an expiry date - generally one year. This means that each year the certificate will need to be updated if local.dynamsoft.com is used.

Resolution

• No High Level Security Requirement: Set back to self-signed certificate “127.0.0.1” by comment the line Dynamsoft.WebTwainEnv.Host = "local.dynamsoft.com" or Dynamsoft.DWT.Host="local.dynamsoft.com" out. No need to worry about the expiry date of the certificate anymore.

• High Level Security Requirement (Please note: you need to replace the certificate annually due to expiration)

  If you have to use “local.dynamsoft.com”, the following methods can be taken:

  • Method 1.Use the following links to download and install the new Dynamic Web TWAIN Service Installer.
    • For Windows

      Choose between Admin (requires admin privileges) or Personal (for individual users).

      • Version 19.2
        • Windows Installer (Admin)
        • Windows Installer (Personal)
      • Version 18
        • Windows Installer (Admin)
        • Windows Installer (Personal)
    • For macOS

      Use the installer matching your SDK version.

      • macOS Installer v19.2
      • macOS Installer v18
    • For Linux

      Select the installer format based on your distribution type.

      • RPM Packages (Red Hat, Fedora, CentOS, etc.)
        • Linux RPM Installer v19.2
        • Linux RPM Installer v18
      • DEB Packages (Ubuntu, Debian, etc.)
        • Linux DEB Installer v19.2
        • Linux DEB Installer v18
      • ARM64 Architecture
        • Linux ARM64 DEB Installer v19.2
        • Linux ARM64 DEB Installer v18
      • MIPS Architecture
        • Linux MIPS DEB Installer v19.2
        • Linux MIPS DEB Installer v18

  • Method 2. Click here to download the new certificate and use the new server.pem.ldsc & server_key.pem.ldsc to replace the old one in the cert folder under the service’s installation folder. Then restart Dynamic Web TWAIN Service.

  • Method 3. Contact Dynamsoft for a new service installer for client-side. Please specify the exact service version build number found from the version your client currently has installed.

  • Method 4. You can also generate the certificate by yourself. Check out this post.

Original post creation date: Dec 01, 2021

Last modified date: Nov 05, 2025