Ninja Forms incompatible with Pro?

[Hockenberry]

My primary site (multisite WP) has been operating with Pro theme (different pro child theme enabled for each of the multisites) for some time without issue. Just purchased Ninja Forms, installed and configured a basic form, and added shortcode to page – form never populates, and I am getting js errors in the console.

Error in console:
front-end-deps.js?ver=3.4.22:92 Uncaught ReferenceError: Backbone is not defined
at front-end-deps.js?ver=3.4.22:92
(anonymous) @ front-end-deps.js?ver=3.4.22:92
front-end.js?ver=3.4.22:1 Uncaught ReferenceError: Backbone is not defined
at front-end.js?ver=3.4.22:1
at u (front-end.js?ver=3.4.22:1)
at d (front-end.js?ver=3.4.22:1)
at u (front-end.js?ver=3.4.22:1)
at d (front-end.js?ver=3.4.22:1)
at u (front-end.js?ver=3.4.22:1)
at d (front-end.js?ver=3.4.22:1)
at u (front-end.js?ver=3.4.22:1)
at d (front-end.js?ver=3.4.22:1)
at u (front-end.js?ver=3.4.22:1)

To debug, I iteratively disabled all plugins (both site wide and for this site) – no change, Ninja form still not populating
I then disabled Pro, using Twenty Nineteen – Ninja form populated correctly, pointing to a conflict with the theme.

I tried upgrading to the most recent version of Pro (3.1) – no change

Please advise.

Thanks!

[Hockenberry]

I continued to test, and found the incompatibility is between NinjaForms and a Mailchimp model embed that was included in the header.php for the child theme (which is why the issue happened with the child theme. I have removed the embed, and the form is working.

I would still like to use the embed – any ideas on that?

[alexander]

Hi Dave,

Great to hear you got it worked out! Regretfully, we wouldn’t really be able to help getting a custom embed code working with a third party plugin. That’s a bit outside the scope of support. It might be worth reaching out to Ninja Forms or mailchimp to see if either party can advise on the conflict.

[Hockenberry]

Agreed – I should have directed that to Ninja forms rather than Themeco – sorry!