---
title: "ERR_SSL_PROTOCOL_ERROR on iPhone: cause and fix"
description: "Safari and iOS Chrome share the system TLS stack, so a configuration profile, a content blocker, or a VPN profile can break the handshake for every browser…"
canonical: "https://lemwatch.com/errors/err-ssl-protocol-error/on-iphone"
source: "https://lemwatch.com"
---

# ERR_SSL_PROTOCOL_ERROR on iPhone

> Safari and iOS Chrome share the system TLS stack, so a configuration profile, a content blocker, or a VPN profile can break the handshake for every browser at once.

## Why it happens on iPhone

 Safari and iOS Chrome share the system TLS stack, so a configuration profile, a content blocker, or a VPN profile can break the handshake for every browser at once.

## The fix on iPhone

 Settings → General → VPN & Device Management: remove unknown profiles. Turn off any VPN, then Settings → Safari → Clear History and Website Data.

## If that didn't fix it

 iPhone has its own failure mode, but ERR_SSL_PROTOCOL_ERROR has a wider set of causes. The most common one overall is: The server only offers TLS 1.0 or TLS 1.1, which every current browser has disabled.

 Enable TLS 1.2 and TLS 1.3 on the origin and remove the deprecated versions. On nginx set `ssl_protocols TLSv1.2 TLSv1.3;` and reload.

## Check your own domain

 The SSL checker reads the live handshake: protocol versions offered, cipher suites, chain completeness and expiry. If it cannot complete the handshake either, the fault is server-side and not your browser.

## Frequently asked questions

### Why does ERR_SSL_PROTOCOL_ERROR happen on iPhone?

 Safari and iOS Chrome share the system TLS stack, so a configuration profile, a content blocker, or a VPN profile can break the handshake for every browser at once.

### How do I fix ERR_SSL_PROTOCOL_ERROR on iPhone?

 Settings → General → VPN & Device Management: remove unknown profiles. Turn off any VPN, then Settings → Safari → Clear History and Website Data.

### What does ERR_SSL_PROTOCOL_ERROR mean?

 Chrome tried to start an encrypted connection and the server answered with something that is not valid TLS. In almost every case the server is offering a protocol version or cipher the browser refuses, the certificate is broken, or something on the network is intercepting the handshake.


## Related

- [All causes of ERR_SSL_PROTOCOL_ERROR](https://lemwatch.com/errors/err-ssl-protocol-error)
- [All website error codes](https://lemwatch.com/errors)
- [ERR_SSL_PROTOCOL_ERROR on Mac](https://lemwatch.com/errors/err-ssl-protocol-error/on-mac)
- [ERR_SSL_PROTOCOL_ERROR on Windows](https://lemwatch.com/errors/err-ssl-protocol-error/on-windows)
- [ERR_SSL_PROTOCOL_ERROR on Nginx](https://lemwatch.com/errors/err-ssl-protocol-error/in-nginx)
- [Free SSL certificate check](https://lemwatch.com/tools/ssl-checker)
- [ERR_SSL_PROTOCOL_ERROR on Chrome](https://lemwatch.com/errors/err-ssl-protocol-error/on-chrome)
- [All monitoring checks](https://lemwatch.com/features)