Thread:Extension talk:ExternalLinks/Question mark in Server response

I installed the extension, but in Server response it only shows ? -mark for real external links. But links which are pointed to same wiki http://mywiki.com/wiki/pagename are shown correctly. How would I solve the problem?

My MediaWiki version is 1.22.2 and with $wgELvalidationMode = 'cURL'; the php info for "cURL support" is "enabled".

Thanks!