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When you run into an issue, the first step is most often to test to see if anything on your site is interfering with Formidable to cause the issue. This guide provides a step-by-step process to troubleshoot theme or plugin conflicts.

How to find a conflict

Work through these steps in order. Most issues get resolved before you even reach the conflict test.

1. Are Formidable and WordPress updated?

1. Go to Plugins and check that Formidable Forms (and Formidable Forms Pro, if used) is on the latest version.
2. Go to Dashboard → Updates and check for a WordPress core update.

A past update may already have fixed the issue you're seeing.

2. Is your hosting environment current?

Outdated PHP or database versions can cause unexpected behavior. Go to Tools → Site Health in your WordPress admin to see any flagged issues. Your server's PHP version is on the Info tab, under Server. If your host is behind on requirements, ask them to update it.

3. Is a caching or optimization plugin interfering?

Caching and optimization plugins can prevent form scripts from loading correctly, which often shows up as broken validation or a form that won't submit. Clear your site's cache first. If that doesn't help, use one of these URL parameters to bypass the plugin on a specific page and test again:

• W3 Total Cache: ?nocache=true
• WP Super Cache: ?wp-super-cache=1
• WP Fastest Cache: ?wpfc=1
• LiteSpeed Cache: ?lscache=off
• SG Optimizer (SiteGround): ?nocache=1
• Autoptimize: ?ao_noptimize=1
• WP Rocket: ?nowprocket
• Perfmatters: ?perfmatters=1 (or ?nocache, ?perfmattersoff, ?perfmatterscssoff, ?perfmattersjsoff for narrower tests)

If you use a service like Cloudflare, put it in developer mode while testing.

See the full list with examples in Bypass cache and optimization.

4. Test for a theme or plugin conflict

If steps 1–3 didn't resolve it, run a full conflict test:

1. Deactivate all plugins except Formidable Forms and Formidable Forms Pro. Deactivate Formidable add-ons too.
2. Remove all custom code, including PHP and JavaScript.
3. Switch to the default WordPress theme.
4. Confirm Formidable and WordPress are both on the current version.
5. Clear all caching, on your site and in your browser.

If the issue doesn't show up under these conditions, add each item back one at a time, testing after each, until you find the culprit.

If the issue still isn't resolved, try reverting to a previous version of Formidable Forms.

Test with Troubleshooting Mode

The free Health Check & Troubleshooting plugin runs the conflict test only for you. Its Troubleshooting Mode turns off all plugins and switches to a default WordPress theme for your login session only. Your visitors and other logged-in users still see your site as usual.

1. Install and activate the Health Check & Troubleshooting plugin.
2. Go to Tools → Site Health and click the Troubleshooting tab (1).
3. Click Enable Troubleshooting Mode (2). All plugins now appear inactive for you, Formidable included.
   

   

4. In the admin bar, hover over Troubleshooting Mode and go to Plugins. Click Enable Formidable Forms (3). If you use Formidable Forms Pro, enable it too.
   

   

5. Test your form. If the issue is gone, enable your other plugins one at a time from the same menu. Test after each one until the issue comes back. Use Themes in the same menu to switch back to your own theme.
6. When you're done, click Disable Troubleshooting Mode (4) in the same menu. Logging out also turns it off. It's tied to your browser and IP address, so it also ends if your IP address changes.

Test on a staging site

If this is a live site, you can run the theme or plugin conflict test on a copy of the site (a staging site) instead. You won't need an extra license as long as the staging or development site URL meets one of these conditions.

Some hosts have an easy way to create a staging site. If yours doesn't, you can copy your site using free plugins like All in One WP Migration or Duplicator or any other plugin or system you like. Your host may be willing to create a staging site for you if you ask.

Known theme or plugin conflicts

These themes and plugins are known to cause conflicts with Formidable:

• Admin Menu Tree Page View: When changes are made to the page orders, the form actions in Formidable are moved to the wrong forms.
• Custom User Registration Form Builder: Causes a JavaScript error in the WordPress Dashboard that prevents the default field icons from saving when toggled.
• Disable Blog: Disallows the use of custom posts and may prevent Views from functioning properly.
• Divi theme: Returns a 500 error on the form preview page. The smooth scrolling functionality may prevent Calendar View and Bootstrap 5.0.2 from working properly.
• Download Manager by Shaon: Causes functionality issues with the Bootstrap Modal add-on.
• Duplicate / Clone Pages and Posts: May prevent views and forms from duplicating correctly.
• Facebook Chat: May interfere with the reCAPTCHA working on your site.
• Fast Velocity Minify may prevent File Upload fields from working properly.
• GDPR Cookie Consent: May cause issues with the Views listing display.
• LiteSpeed Cache: May prevent Views from displaying properly. One possible fix is to turn off caching for logged-in users.
• Login with Ajax: Prevents WordPress posts from getting created from forms setup to create posts.
• Ultimate Member: Can make file uploads take significantly longer, and show a 'Hello, Spam Bot' message.
• User Meta: Forces all emails to either HTML or plain text, depending on what is selected in their settings
• W3 Total Cache: With some W3 settings, an incorrect link to uploaded files will be included in the email notification, reCAPTCHA and Math Captcha may not work, and entries will not always be submitted. The W3C database cache function causes uploaded files to not attach to the email.
• WPFront User Role Editor will sometimes lose the ability to un-check capabilities while Formidable is active. This can be circumvented by deactivating Formidable, making your changes, and then reactivating Formidable.
• WPRocket may prevent File Upload fields from working properly.
• The WP reCaptcha plugin may prevent Formidable reCAPTCHAs from functioning.
• WP User Avatar cuts off the CSV export file at 130 KB
• Any plugin or theme that causes JavaScript errors. Themes are the most common offenders by loading a version of jQuery other than the one included with WordPress. Known Plugins: CM Tooltip Glossary

Bypass cache and optimization

To temporarily disable cache for various caching plugins, you can add the following query string to the end of the URL. Although turning off the plugin completely is an option, the method outlined below is often quicker and more effective.

• W3 Total Cache. Use the ?nocache=true parameter to bypass W3 Total Cache on a specific page.

  www.mysite.com/page/?nocache=true

• WP Super Cache. Use the ?wp-super-cache=1 parameter to bypass WP Super Cache on a specific page.

  www.mysite.com/page/?wp-super-cache=1

• WP Fastest Cache. Use the ?wpfc=1 parameter to bypass WP Fastest Cache on a specific page.

  www.mysite.com/page/?wpfc=1

• LiteSpeed Cache. Use the ?lscache=off parameter to bypass LiteSpeed Cache on a specific page.

  www.mysite.com/page/?lscache=off

• SG Optimizer (SiteGround). Use the ?nocache=1 parameter to bypass SG Optimizer (SiteGround) on a specific page.

  www.mysite.com/page/?nocache=1

• Autoptimize. Use the ?ao_noptimize=1 parameter to bypass Autoptimize on a specific page.

  www.mysite.com/page/?ao_noptimize=1

• WP Rocket. Use the ?nowprocket parameter to bypass WP Rocket on a specific page.

  www.mysite.com/page/?nowprocket

• Perfmatters. Use the ?perfmatters=1 parameter to bypass Perfmatters on a specific page.

  www.mysite.com/page/?perfmatters=1

  Use the ?nocache parameter to test the page without cache.

  www.mysite.com/page/?nocache

  Use the ?perfmattersoff parameter to test the page without cache and disable all kinds of optimization.

  www.mysite.com/page/?perfmattersoff

  Use the ?perfmatterscssoff parameter to test the page without cache and disable CSS optimizations.

  www.mysite.com/page/?perfmatterscssoff

  Use the ?perfmattersjsoff parameter to test the page without cache and disable JS optimizations.

  www.mysite.com/page/?perfmattersjsoff