How to display all when input argument is wrong
For contextual filters, the Views UI allows you to specify two different cases:
Case 1: If the filter value is not passed to the URL
In the contextual filter configuration, in the &quot;When the filter value is not in the URL&quot; section, you need to set the &quot;Display all results for the specified field&quot; option.
Case 2: If the filter value is wrong
In the contextual filter configuration, in the &quot;When the filter value IS in the URL or a default is provided&quot; section, you need to check the &quot;Specify validation criteria&quot; checkbox. Then, you can set the &quot;Action to take if filter value does not validate&quot; to &quot;Display all results for the specified field&quot;.
You can see more details in the Views documentation: https://www.drupal.org/node/1578574
Hope it helps,