How to fix the SSL VPN connection error after upgrading to iOS 13 and macOS 10.15

Apple has changed their certificate security requirements, and it affects the SmartVPN app on iOS13 and macOS 10.15 to create a connection if the Vigor VPN servers are using Self-Signed Certificate.

To meet the new security policy of Apple, we have two solutions:
1. For a better security level, we recommend applying for a DrayDDNS domain and sign it with Let's Encrypt or import a local CA signed by a Certification Authority.
After that, selecting the CA on SSL VPN >> General Setup.
For more configuration information, please refer to this article, Use Let's Encrypt Certificate for your DDNS Domain

2.  Using the following firmware version and regenerate the new Self-Signed Certificate

3.8.9.6 for Vigor2860/Vigor2925; 3.9.1.2 for Vigor 2952/ Vigor3220; 3.9.1.3 for Vigor 2926/ Vigor2862

Please follow these steps to regenerate self-signed certificate

1. Navigate to System Maintenance >> Self-Signed Certificate (2860/2925) or Certificate Management >> Self-Signed Certificate
2. Click Regenerate

3. Put the information, then click generate.
4. Make sure your SSL VPN is choosing Self-Signed Certificate.