Leads being rejected due to INVALID_FORMAT literally means that some data for your lead isn't in the correct format, this can be things such as text being submitted to a number field.

To avoid this issue, it's essential that when you set up your campaign, and any landing page, import, or API code, that your data matches the field and it's validation requirements.

The next thing to look at is to make sure the fields and their validation in Databowl match the format you are submitting.

An example we frequently see with this is with age fields.

If your data (from a landing page, import, or API) is based on Age Ranges or Bands such as 55-59, but your field is set up as a number it will fail.

This is because 55-59 contains a non-numerical character, so it's not a number, and should be a text field.

To solve this, rename your old field to something like age_old, and create a new text field called age.

You can also have this issue when importing data. In this instance, the first thing to check is that your fields match your data correctly.

Occasionally when importing a CSV columns can be incorrect and things can happen such as phone numbers being aligned to the email address columns. The fix here is to correct your CSV and reattempt import.

Similar issues can happen with your API scripts, so make sure you check the variables are correctly mapped.

And remember, if you're still having issues, we're always here to assist.