> For the complete documentation index, see [llms.txt](https://docs.verifone.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.verifone.com/support-nordics/p400-two-piece-sa/errors/ssl-certificate-missing-ssl-handshake-missing.md).

# SSL Certificate Missing / SSL Handshake Missing

What to do when your P400 Two-Piece customer unit shows SSL Certificate missing or SSL Handshake missing — check the network connection, then contact Support.

{% hint style="info" %}
**Use this page when** your **customer unit (P400)** shows **"SSL Certificate missing"** or **"SSL Handshake missing"**.
{% endhint %}

<details>

<summary>Keywords</summary>

Also called: SSL certificate missing, SSL handshake missing, SSL error, certificate error, handshake failed, secure connection error, network fallback. Search terms: SSL, certificate, handshake, connection, LAN, Wi-Fi, network fallback, default, network test, customer unit, P400.

</details>

## Symptoms

You may see one or more of the following:

* The **customer unit (P400)** shows **"SSL Certificate missing"** or **"SSL Handshake missing"**.
* Payments fail or the terminal can't connect to our system.

**Most likely cause:** the customer unit can't make a secure connection to our system. This is often because it has lost its network connection, or its network settings don't match the connection it's using.

## Before you start

This message appears on the **customer unit (P400)** — the unit your customer uses to pay.

To open the menu on the customer unit, press **4** and **6** at the same time, then enter password **1234** and press the **green button**.

## Resolution

Work through **Steps 1 to 3**, then try a test transaction in **Step 4**.

{% stepper %}
{% step %}

### Check the customer unit is connected to the network

1. On the customer unit, open the menu.
2. Select **Administration > Settings > Communications**.
3. Check whether **LAN** or **Wi-Fi** shows as **UP**.

* **If one shows UP:** note which one it is — you'll need it in Step 2.
* **If neither shows UP:** the customer unit isn't connected to your network. Reconnect it using [How to Connect the Cables](/support-nordics/p400-two-piece-sa/how-tos/how-to-connect-the-cables.md) (network cable) or [How to Set Up Wi-Fi](/support-nordics/p400-two-piece-sa/how-tos/how-to-set-up-wi-fi.md) (wireless).

Then continue to Step 2.
{% endstep %}

{% step %}

### Check the Network Fallback setting

The **Network Fallback** setting tells the terminal which connection to use. If it doesn't match the connection you're using, the terminal can't reach our system — even if it's connected.

1. On the customer unit, open the menu.
2. Select **Administration > Settings > Network Fallback**.
3. Select **Default** and make sure the connection you're using is ticked:
   * **Ethernet** if the terminal uses a network cable.
   * **Wi-Fi** if the terminal uses a wireless connection.
4. Press the **yellow back arrow** key.
5. Select **Fallback 1** and make sure **None** is ticked.
6. Press the **red button** until you're out of the menu.

{% hint style="warning" %}
**Fallback 1** should always be set to **None**. Don't select another connection here unless Verifone Support asks you to.
{% endhint %}

Then continue to Step 3.
{% endstep %}

{% step %}

### Run a network test

Run a network test to confirm the terminal is connected — see [How to Do a Network Test](/support-nordics/p400-two-piece-sa/how-tos/how-to-do-a-network-test.md).

* **If the test fails:** go back to Step 1 and check the connection again, or go to Step 5 and contact Verifone Support.
* **If the test passes:** continue to Step 4.
  {% endstep %}

{% step %}

### Try a test transaction

Try a test transaction to check whether the message has gone.

✅ **Transaction works and the message has gone — stop here.** ❌ **Message still appears — continue to Step 5.**
{% endstep %}

{% step %}

### Contact Verifone Support

If the message still appears, <mark style="color:red;">contact Verifone Support</mark>. Our team will send and load a new certificate to your terminal.
{% endstep %}
{% endstepper %}

**If the message has gone.** No further action needed.

**If the message still appears.** Contact Support below.

## Still not working?

{% hint style="info" %}
**Still need help? Contact Verifone Support.**

If the steps above haven't resolved the issue, <mark style="color:red;">contact Verifone Support</mark>. Tell us the troubleshooting steps you've already tried — it helps us get you to the right support faster.
{% endhint %}


---

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