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

The error occurs If you have not deactivated the free version of the Ivory Search plugin so please deactivate and delete the free version of the Ivory Search plugin before installing the premium version of it.

Best regards,
Ivory Search Support

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

I could confirm the issue on your shared website.

Are you using any other search plugin that may conflict with the Ivory Search plugin functionality?

If yes then please try deactivating that plugin.

This can be a theme issue used on your site so to confirm it just temporarily use the Twenty Twenty theme on your site. If everything works fine then it’s your site theme issue.

Would you mind if I log in to your staging 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 checking the option “Set as private reply” when replying to this topic?

Best regards,
Ivory Search Support

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/

I’d really appreciate that. 🙂

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

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

This seems the iPhone a related issue as described on the below pages.

https://stackoverflow.com/a/7879177
https://stackoverflow.com/a/2918716

You can try resolving it by adding the below CSS code in the Custom CSS option of Ivory Search plugin settings on the path Ivory Search -> Settings -> Settings

.is-form-style input.is-search-input {
    -webkit-appearance: none;
    -webkit-border-radius: 0;
    border-radius:0;
}

Best regards,
Ivory Search Support

Could you please clear the cache of wpo-minify and temporarily deactivate it on your website?