ACP / Rewrite URLs gives EX0 error in 4.0.12.1?

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Can someone else who has "Rewrite URLs" enabled and IPS is installed in a subdirectory just double-check that you can still access System -> Search Engine Optimization after upgrading to 4.0.12.1? I now get an EX0 error (no entry in error log). I can reproduce on a clean install. As soon as I enable Rewrite Urls (and install the htaccess) that page starts to error. 

The settings is still working, my URLs are working ok, but the ACP page is now inaccessible.

 

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Solved it. Basically it's a combination of SSL/SNI and Socket/Curl versions.

I'm running Centos 6.6 and Plesk Panel which as the default configuration uses nginx as a reverse proxy to apache (so all the normal apache rewrites work). Centos 6.6 comes with Curl 7.19 so the IPS software ignores curl and uses sockets. Not usually a problem.

In the ACP there is a bit of code on the Rewrite Urls page that does this: "If Apache and RewriteURLs Then Make a call to my board url and see if it works". Last week I turned off the nginx proxy and went back to pure apache this was why I only just saw the error in the ACP. Last week the software didn't "think" I was running apache even though I was.

It was this http request that was completely failing and that was causing the error. Centos 6.6 sockets don't appear to work with SSL when SNI is being used (multiple hostnames and certificates on a single IP address). Forcing the use of Curl (creating a constants.php with FORCE_CURL) also didn't work. Curl 7.19 can't handle it either.

I manually upgraded to curl 7.43 (didn't want to because I like to keep stock centos as much as possible) and the error was no more.

The IPS installation or ACP routine should probably check for SSL board addresses with a Curl version of <7.36 to catch this configuration. Centos 6.6 is a recent version so it's not an uncommon scenario once more people start implementing SSL.