Denis Ryabov

Do you have “Keep extra link tag attributes” option enabled in “Minify CSS” section of Advanced settings tab?

In the case of blank page with libxml, are there related error/warning messages in error_log? Also you could try to temporary enable error logging in “Troubleshooting” section to collect all PHP errors, warnings, and notices in wp-content/plugins/psn-pagespeed-ninja/includes/error_log.php file.

Попробуйте в Advanced-настройках переключить параметр “HTML Parser” в значение “Use Standard full HTML parser”. (Не уверен на 100%, что причина именно в этом, но в Fast simple и libxml парсерах были найдены небольшие ошибки, которые будут исправлены “as soon as possible”)

Fixed in 0.9.22.

Could you post a screenshot of your issue? And what browser do you use?

OK. The problem is in “Load external files” feature, you can disable it in “Leverage browser caching” section of Advanced settings tab. It will be fixed in the next PageSpeed Ninja release.

We have just released PageSpeed Ninja 0.9.21 with several improvements and bugfixes. Could you check it?
PS. Our email is: hello (at) pagespeed.ninja

Fixed in 0.9.21.

Fixed in 0.9.21.