Most common reasons:
1. Hidden fields
If the prefill fields are not part of the form, enable prefilling hidden fields.
The first step in troubleshooting a hidden prefill is to unhide the field and make sure that it's actually being prefilled.
2. Incorrect encoding syntax
Make sure that your prefills are correct. For example:
Should instead be:
3. Incorrect field name
Make sure the field name in the prefill URL matches the actual field name in Airtable, not the custom title you have in the form. And it's case-sensitive!
4. The field is read-only.
If the field is set to read-only, that will cause prefilling to not work. Prefilling is a form of editing. You must enable the "Allow URL prefills" toggle to allow it for read-only fields.
On the legacy site app.miniextensions.com
If you're still using our legacy form, there could be other reasons:
The base is out of sync
If you just added a new field to your table, make sure the base structure in miniExtensions is synced with Airtable.
If the field type is a checkbox, you'd need to prefill it with the value "checked" instead of "1".