How to Reinstall the DYMO Web Service Certificate
Overview
If your DYMO label printer isn’t reachable via web pages, or you’re encountering SSL-related errors—such as “None of these ports were configured to use SSL certificate,” “TrustFailure,” or “SecureChannelFailure”—your DYMO Web Service certificate may be corrupted or improperly installed. This guide walks you through the complete reinstall process for both Windows and macOS systems.(dymo.co.za)
For Windows
Step 1: Remove the Printer & Uninstall Software
Log in as an Administrator.
Remove the DYMO printer by following the official printer-removal guidance. (Refer to DYMO’s specific article.)(dymo.co.za)
Perform a clean uninstall of the DYMO software. (Refer to DYMO’s uninstall guide.)(dymo.co.za)
** Important:** Do not reinstall the software before you remove the existing certificate.
Step 2: Remove the Web Service Certificate
Open the Run dialog (Win + R), type
certlm.msc, and press Enter to open Certificate Manager.(dymo.co.za)Navigate to:
Certificates – Local Computer → Trusted Root Certification Authorities → CertificatesLocate and delete:
DYMO Root CA (for localhost)
Empty the Recycle Bin, then restart your computer.(dymo.co.za)
Step 3: Reinstall the Software
Run the DYMO software installer.(dymo.co.za)
After installation, restart your computer.
Step 4: Set Up and Test the Printer
Reconnect the printer and power it on.
Pick DYMO Authentic labels, orienting them correctly (labels facing down, aligned left).
Reconnect via USB or LAN to your computer.
Look for the DYMO icon in the system tray (bottom-right). Right-click and choose Diagnose.
If you see "DYMO Connect Service is running" (or similar), the certificate is properly installed.(dymo.co.za)
For macOS
Step 1: Remove Printer & Uninstall Software
Log in with Administrator privileges.
Open System Preferences → Printers & Scanners, and delete the DYMO printer.
Quit the DYMO Web Service if it's active in the menu bar.(Amazon Web Services, Inc., dymo.co.za)
Step 2: Remove the Web Service Certificate
Open Finder → Utilities → Keychain Access.
Select System on the left, then click Certificates.
Delete:
DYMO Root CA (for localhost)
localhost certificate (if issued by DYMO).
Empty the Trash and restart your computer.(dymo.co.za, Amazon Web Services, Inc.)
Step 3: Reinstall the Software
Run the DYMO installation file. If prompted during setup, a command prompt dialog may appear—type your Administrator password (it will be invisible as you type), then hit Enter.(dymo.co.za, Amazon Web Services, Inc.)
After installation, the DYMO icon should show up in the menu bar.
Step 4: Diagnose and Confirm Certificate Installation
Click the DYMO icon and select Diagnose.
If you see "DYMO Connect Service is running", the certificate is installed and functioning properly.(dymo.co.za, Amazon Web Services, Inc.)
Tips & Best Practices
Always ensure you’re running as an Administrator—both for installing/uninstalling software and modifying certificate stores.
For multi-user environments, ensure all relevant user accounts are granted necessary permissions (particularly on Windows, see advanced permissions guidance).(help.navigate360.com)
Keep the DYMO software updated—some earlier versions suffered SSL certificate issues; updating can resolve them.(Stack Overflow)
Quick Reference Table
Platform | Remove Printer & Uninstall Software | Remove Certificates | Reinstall Software | Diagnose |
Windows | Log in as Admin → Remove printer → Clean uninstall |
| Run installer → Restart | Tray icon → Diagnose → Look for “Service is running” |
macOS | Admin login → Delete printer → Quit Web Service | Keychain Access → System → Delete certificates | Run installer → Enter password when prompted | Menu bar icon → Diagnose → Confirm service running |