> For the complete documentation index, see [llms.txt](https://docs.tapxphone.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.tapxphone.com/guide/app-guide/trusted-devices/device-blocked.md).

# The device is locked for the App

While using the Application, your device is constantly checked for compliance with the Security Criteria.

{% content-ref url="/pages/-MZYy0Ty-Zi28XQyJU\_n" %}
[Trusted Device Criteria](/guide/app-guide/trusted-devices.md)
{% endcontent-ref %}

If the state of a device does not meet the requirements set by the system, it can be blocked in terms of using the Application, as the device may present a threat to the safe acceptance of card payments.

{% hint style="warning" %}
In some situations (instead of blocking), the application settings will be reset to their initial state, so you need to [setup your device](/guide/app-guide/device-setup.md) again. 
{% endhint %}

To find out the possible reason for blocking and to request to unlock the device, contact the support service of your Acquiring Service Provider.

{% hint style="info" %}
When addressing the support, please provide the device ID <img src="/files/-MZUdzNm3w1h2qwYhPX_" alt="" data-size="original"> displayed on the Application’s `Sign in` screen.
{% endhint %}