This can be due to plugin conflict on your site so please try temporarily deactivating all plugins except Ivory Search plugin and see whether everything works fine and then enable the plugins one by one to see which plugin is conflicting if any.

Also, would you mind if I log in to your site and do quick troubleshooting? If this is ok then could you please temporarily create an admin user account and share me the account login details privately by adding them in the box having text “Enter your private content here (only you and forum moderators will be able to see it)”?

I hope you are well today and thank you for your question.

It seems conflicting with your theme mobile menu functionality.

You can resolve this by always displaying the search form input box on the mobile menu. To do that, just add the below CSS code in the Custom CSS option of Ivory Search plugin settings on the path Ivory Search -> Settings -> Settings

.et_mobile_menu li.is-menu a {
    display: none;
}
.et_mobile_menu li.is-menu form.is-search-form {
    position: static;
    width: auto;
    max-width: 100%;
}
.et_mobile_menu .is-menu form label,
.et_mobile_menu li.is-menu input.is-search-input {
    max-width: 100%;
}

Best regards,
Ivory Search Support

I have released the updated plugin version.

Please update the plugin on your website and let me know how it works for you.

You are always welcome, I’m glad I was able to help you with this matter. There is no obligation but by your kind words I wonder if I could trouble you to leave a review based on this experience here:

https://wordpress.org/support/plugin/add-search-to-menu/reviews/?filter=5

I’d really appreciate that. 🙂

And if I can be of any further assistance please don’t hesitate to ask.

I could confirm the issue and resolved it in the plugin version 4.4.14 which will be released soon.

Thank you for your cooperation.