Hi!
I need a little more information to be able to assist you, as I don’t see the plugin activated at the moment.
– Is the issue that the plugin does not replace the default search bar? If so, it’s most likely because the theme does not support automatic replacement of the search bar. (it’s not using searchform.php file to display the search) In this case the only possibility is to replace the search manually within the theme files with the plugin shortcode.
– Or is the plugin not working at all? I suspect this is the issue, as I can already see a fatal error message on the javascript error console, which prevents further script execution, causing issues: https://i.imgur.com/RTJA1Fp.png
It’s either the auto optimizer causing it, or the problem was already there before the optimization.
I highly suggest fixing this issue, as it may cause other plugins or elements to malfunction (even if this wasn’t the problem with ajax search lite).
Also, there is different script loading method implemented in ajax search lite, which might be able to get around the error and still load correctly.
On the Compatibility Settings submenu, change the Javascript source option to “Minified scoped”: https://i.imgur.com/lSxWj9A.png
Make sure to clear your cache after this change.