# Firefox: Secure Connection Failed — SSL received a record that exceeded the maximum permissible length. Error code: SSL_ERROR_RX_RECORD_TOO_LONG

**Code:** `SSL_ERROR_RX_RECORD_TOO_LONG` · **Category:** SSL / TLS · **Seen on:** SSL, Nginx

Firefox sent a TLS handshake but received plain HTTP back — you used `https://` on a port that serves HTTP.

## Meaning

Most often the site is not configured for TLS on that port: Apache/Nginx listening on 443 without `ssl`, a development server on 8080 with HTTP only, or an `https://` link to a non-TLS service. Use `http://` or enable TLS on that port.

## Common causes

- https:// used against an HTTP-only port
- Nginx `listen 443;` without `ssl`
- Apache vhost on 443 without `SSLEngine on`
- Proxy forwarding HTTPS to an HTTP backend port
- Dev server (Node/Python) started without TLS

## Quick fix

1. Use `http://` or the correct port
2. Add `ssl` to the listen directive and load certificates
3. Check: `curl -v http://host:port` vs `https://host:port`

## Detailed fix by platform

### Linux

1. `curl -v https://host:8080 2>&1 | head` shows `wrong version number` when the port speaks plain HTTP

## How to diagnose

1. **Port** — TLS enabled?
2. **Scheme** — http vs https?
3. **Config** — ssl on?

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Source: [WhatIsMyError](https://whatismyerror.com/errors/ssl/ssl-error-rx-record-too-long)