I have no knowledge of any similar issues.
Is there any error message, or anything related in the error logs?
While it's almost impossible to tell the source of the problem without seeing the code, I'm suspecting a 3rd party plugin issue. The most probable thing is that another plugin might use a class or function name same as in the search, but without checking it's existence first – leading to a re-declaration error. It's a very common mistake by many plugin devs.
I suggest temporarly disabling all plugins and switching the theme to default and activating ajax search pro. If no crash, then it's almost definitely caused by another plugin or the theme.
A faster way is, if you can provide temporary log-in and FTP details, and I can debug through the search code via FTP to see where the execution stops.Best,
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