# Chrome: Connection not secure — ERR_SSL_OBSOLETE_VERSION (old TLS 1.0/1.1)

**Code:** `ERR_SSL_OBSOLETE_VERSION` · **Category:** Browser · **Seen on:** Chrome, Edge

The server only supports an outdated TLS version that current browsers no longer allow.

## Meaning

Chrome and Edge removed TLS 1.0 and 1.1. Old intranet servers, printers, routers and embedded devices are the main victims. The proper fix is to enable TLS 1.2 or higher on the device; as a last resort use an older browser inside a controlled network or put a modern reverse proxy in front.

## Common causes

- Server, appliance or load balancer limited to TLS 1.0/1.1
- Old firmware on routers, printers, NAS, IPMI/iLO consoles
- Legacy .NET/Java stack with TLS 1.2 disabled
- Hardened OS policy disabling modern protocols for the server

## Quick fix

1. Update the device/server firmware or software and enable TLS 1.2+
2. Put an nginx/Apache reverse proxy with modern TLS in front of a legacy device
3. Do not re-enable obsolete TLS in the browser for the open internet

## Detailed fix by platform

### Nginx

1. Front the legacy host: `server { listen 443 ssl; ssl_protocols TLSv1.2 TLSv1.3; location / { proxy_pass http://192.168.1.10:80; } }`

### Windows

1. For old IIS: enable TLS 1.2 via registry/IIS Crypto and update to a supported .NET version

## How to diagnose

1. **Version** — Which TLS versions does the host offer?
2. **Device** — Firmware update available?
3. **Exposure** — Internal-only or internet-facing?

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Source: [WhatIsMyError](https://whatismyerror.com/errors/browser/err-ssl-obsolete-version)