# Apache: [proxy_http:error] AH01102: error reading status line from remote server 127.0.0.1:3000 / AH00898: Error reading from remote server returned by /api

**Code:** `AH00898: Error reading from remote server (502 Proxy Error)` · **Category:** Nginx / Apache · **Seen on:** Apache, Linux

mod_proxy couldn't read a valid response from the backend, so Apache returned 502/503.

## Meaning

The backend crashed, closed the connection, speaks a different protocol, or responded too slowly. Check the backend log, `ProxyTimeout`, and that `ProxyPass` points to the right scheme/port. Set `SetEnv proxy-initial-not-pooled 1` or `ProxyPass ... disablereuse=On` for keepalive races.

## Common causes

- Backend crashed/restarted
- HTTP vs HTTPS mismatch to the backend
- Timeout (`ProxyTimeout`) too low
- Keepalive connection reuse race
- Backend not running (AH00957 / AH01114 variants)

## Quick fix

1. Check the backend service and its log
2. Match the protocol/port in `ProxyPass`
3. Tune `ProxyTimeout` and `disablereuse=On`

## Detailed fix by platform

### Linux

1. `sudo tail -30 /var/log/apache2/error.log; curl -I http://127.0.0.1:3000/`

## How to diagnose

1. **Backend** — Alive?
2. **Scheme** — http vs https?
3. **Timeout** — ProxyTimeout?

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Source: [WhatIsMyError](https://whatismyerror.com/errors/nginx-apache/apache-ah00898-error-reading-from-remote-server)