SAML VPN Authentication Fails After DNS Moved to GoDaddy

Hi Waseem Syed,

Welcome to Microsoft Q&A forum.

Please try to follow the below suggestions:

Check DNS Record Configuration: Make sure that your DNS records are properly configured with GoDaddy, ensure the below points

• A Record: Should point to the IP address of your FortiGate.
• CNAME Record: If applicable, should point to the Fully Qualified Domain Name (FQDN) for the FortiGate.
• TXT Record: Might be needed for domain verification with certain services.

Reference link:https://learn.microsoft.com/en-us/azure/app-service/manage-custom-dns-buy-domain#manage-custom-dns-records

Verify SSL/TLS Certificate: Ensure that the SSL/TLS certificate for your domain is valid and properly installed on the FortiGate. Certificate errors can arise if the certificate has expired or if there's a mismatch in the domain name

Ensure the certificate used for the SSL-VPN portal is:

• Publicly trusted or issued by a CA that the client trusts.
• Matches the FQDN configured for the VPN portal.

If you’re using a self-signed certificate, FortiClient will often block the page unless the certificate is installed in the client’s trusted store.

you can follow the below reference link for better understanding.

Reference link:https://learn.microsoft.com/en-us/troubleshoot/azure/app-service/connection-issues-with-ssl-or-tls/troubleshoot-domain-and-tls-ssl-certificates?source=recommendations#custom-domain-problems

Verify Redirect URI and SAML Settings:

• In Azure AD Enterprise Application:
  • Confirm the Reply URL (Assertion Consumer Service) matches the FortiGate configuration.
  • Ensure the Identifier (Entity ID) is correct.
• On FortiGate:
  • Check that the Single Sign-On URL and Entity ID match Azure AD settings.
  • Confirm the Certificate used for SAML is valid and not expired.

Inspect Firewall Settings: Check if any firewall rules are blocking access to the FortiGate or Azure services & ensure that the necessary ports are open for SAML authentication.

Hope, you find this comment helpful, if yes, please “up-vote” for the information provided , this can be beneficial to community members.

Kindly let us know if you have any additional questions.

Thanks