The requestErrorText configuration parameter sets the error message text that will appear in data-ajax-cart-messages containers when a Shopify Cart API request is not successful and doesn’t have any error description, or if the request is not performed at all due to internet connection, for example.

By default the text is “There was an error while updating your cart. Please try again.”.

You can change the message if your store language is not English or the phrase doesn’t fit to your store:

{% comment %} Somewhere in layout/theme.liquid {% endcomment %}

<script type="application/json" data-ajax-cart-configuration >
    "requestErrorText": "{{ 'general.request_error' | t }}"

You can also use the configureCart function:

<script type="module">
  import { configureCart } from '{{ "liquid-ajax-cart-v1.10.1.js" | asset_url }}';

  configureCart('requestErrorText': 'My request error text');