Critical Error when submitting form Application

For the application form, we are using "The third party post plugin is what we use to send things to Google Sheets for Lead Tracking, "
This is the error I see logged on the server:
[Thu Apr 15 01:35:48.157995 2021] [php7:error] [pid 25682] [client] PHP Fatal error: Uncaught Error: Call to a member function get_input_type() on null in /nas/content/live/optimistic/wp-content/plugins/gravityplus-third-party-post/includes/class-addon.php:953\nStack trace:\n#0 /nas/content/live/optimistic/wp-content/plugins/gravityplus-third-party-post/includes/class-addon.php(698): GFP_Third_Party_Post_Addon->get_request_body(Array, Array, Array)\n#1 /nas/content/live/optimistic/wp-content/plugins/gravityplus-third-party-post/includes/class-addon.php(676): GFP_Third_Party_Post_Addon->post_data_to_external_api(Array, Array, Array)\n#2 /nas/content/live/optimistic/wp-content/plugins/gravityforms/includes/addon/class-gf-feed-addon.
All gravityforms plugins seem up to date. Can you please help me out on this Addon issue.

Hi Flynn. You would need to check with whoever created the “gravityplus-third-party-post” for assistance. That software is calling a function on a null value, and that results in the server error you are seeing. The issue is not with Gravity Forms, but with this add-on which interacts with Gravity Forms. Thank you.

From the nature log message, “Call to a member function get_input_type() on null” it reads as if the add-on isn’t interpreting a specific field / field value correctly to map into the output. In addition to a potential coding issue with the add-on mentioned, if you have any plugins that provide custom field types that might be another area to focus. Perhaps also test in a separate form with some of the basic Gravity Forms field types.

If you find that it is not an easy fix with the plugin you’ve started with, you may want to look at Gravity Flow and it’s outgoing webhook step type. We/it are one of the Certified Developers and add-ons for Gravity Forms and the webhook step provides an easy UI to setup form field mapping to API body. Or our integration with Zapier provides a wealth of other patterns that may suite.