FortiClient vpn issue

What's the FOS version? Run below debugs and attach the output.

dia debug reset
dia debug application sslvpn -1
dia debug application samld -1
dia debug enable

https://community.fortinet.com/t5/FortiGate/Troubleshooting-Tip-Companion-for-troubleshooting-SSL-VPN-with/ta-p/217719

It seems like the upgrade to version 7.4 on iPhone has caused an issue with SSL VPN settings, particularly with SAML authentication using port 443.

Error message:
"VPN Error: unable to get SSO port"

Solution:

The error occurs due to a configuration issue when the client is upgraded. The config on the device needs to be updated manually.

• The port number in the Server Address field should be placed after the hostname (e.g., vpn.domain.com) and not after the realms name.

Alternatively, you can simply remove the existing configuration and add it again.

We're seeing the exact same issue.   Fortios 6.4    app immediately throws the Unable to get sso port.   seems like it isn't even reaching out to try and connect...   creating new connection,  or editing  all results in the same issue...   anybody have any  insights?

I was facing exactly the same issue. Tried to uninstall, reinstall and reconf the App.

I tried different configurations and found the right one:

https://mycompagnyurl.com:443/mycompanyname

same 443 in to Port field.