Description

The subscription endpoint returns HTTP 500 for clients on XHTTP (SplitHTTP) inbounds. The share link in the client info panel generates correctly, but the subscription service crashes when trying to generate the same link.

Steps to reproduce

1. Create a VLESS inbound with xhttp transport and reality security
2. Add a client with a Subscription ID
3. Access the subscription URL: https://host:port/sub/<subscription_id>
4. Returns HTTP 500 with empty body

Expected behavior

The subscription endpoint should return the base64-encoded VLESS share link, same as what the client info panel shows.

Working vs broken

• VLESS-Reality (tcp) subscription: works
• VLESS-WS subscription: works
• VLESS-XHTTP subscription: 500 error
• VLESS-XHTTP share link from info panel: works (correct vless:// link generated)
• Combined Reality + WS subscription (same Subscription ID): works
• Combined Reality + XHTTP subscription: 500 error

Environment

• 3x-ui v2.8.11
• Xray-core 26.3.27
• Docker deployment