Can you check if these files exist at wp-content/plugins/ajax-search-pro/cache/ folder? I can’t do it unfortunately. The 403 usually means a permission related issue. Try to chmod the wp-content/plugins/ajax-search-pro/cache/ folder and all files in it to 777 or 755 or 666.
Where exactly did you get these error codes? Which file throws these errors?
I could see some images in results, I thought that’s all there is.Best,
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