Submitting a Survey123 via the List widget in Experience Builder failed with error: 400 Invalid redirect_uri.

Description

When submitting a Survey123 form via the List widget in ArcGIS Experience Builder, users may encounter the following error:

400 Invalid redirect_uri

Cause

This occurs when the email field contains the 'at' symbol (@) or other special characters that are not properly URL encoded. Because URLs cannot contain certain characters directly, these unencoded characters make the redirect URL invalid, causing the survey submission to fail with a “400 Invalid redirect_url” error. 

Solution or Workaround

1. Identify fields in the survey URL that may contain special characters, for example, email addresses and text fields.
2. Update the Arcade expression used in the List widget or pop-up to encode these fields and use the UrlEncode function before the field.

Example:

UrlEncode($feature["td_email"])

3. Test the survey submission in the List widget to confirm that the URL parameters are properly encoded.