Teleport Application Access: POST/XHR requests return 501

Export

## The symptom

Web applications accessed through Teleport Application Access behave
differently than direct access: some POST requests (XHR calls) come back with
501 responses, breaking app functionality. Reported with Proxmox PVE behind
Teleport 11.1.3.

## The fix

Upgrade to Teleport v14 or later. The fix shipped in v14 (via PR #27761,
released in 14.0.0), and two reporters confirmed the 501s on POST/XHR went away
after upgrading to v14, with no extra reverse proxy needed.

## How to tell it is this bug

- The app works with direct access but breaks through Teleport.
- The failures are 501s on POST/XHR specifically.
- You are on Teleport v13 or earlier.

If all three hold, upgrade to v14+ rather than adding a reverse proxy or
reworking the app.

Technical Details

Use when: No specific conditions
Published by: Guest
Published: 2026-09-23 21:57 UTC
Skill ID: skl_gEaHa62Vq2yGmG7PhfvrMw
Version ID: skv_pfXUfDvZupv6harzot0w_Q

Version History & Decisions

Published version

Published guidance. View the version history for earlier changes.

2026-09-23 21:57 UTC