Can you link me to a page, where the search is enabled, perhaps with phrases you are trying to search for?
My first guess would be a visual editor conflict, but I can't confirm that yet. Some visual editors store the post data outside the posts table, which makes it impossible to look for, but I highly doubt that this is the case now.
It's more likely, that the ajax request gets stuck somwhere, I might need an temporary ftp account to confirm that, and to do a quick debugging on the search code.
I looked at the configuration, it looks fine, so it's not that.Best,
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