Title: Solution for server error 500
Last modified: August 31, 2016

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# Solution for server error 500

 *  [bartbeat](https://wordpress.org/support/users/bartbeat/)
 * (@bartbeat)
 * [10 years, 2 months ago](https://wordpress.org/support/topic/solution-for-server-error-500/)
 * It lasted many hours to find all the pieces, but this solved my problem.
 * Before activation of Polylang: I tried to change the existing TwentyFifteen WP
   theme (with my own language: nl) to another theme (Odio): no problem. Everything
   works just fine!
 * I returned to the TwentyFifteen WP theme. After activating Polylang and translating
   every item in 2 languages: The site works fine.
    I tried again to change the 
   existing TwentyFifteen WP theme (with two languages: en + nl) to Odio (by activating
   it in the Themes window) and I got immediately a ‘Server error 500’…!
 * There are no plugins activated besides Polylang. Everything is up to date (WP
   4.4.2, PHP 5.5.31).
 * I tried to fix it:
    (1) Follow these steps: [How to Deactivate All Plugins When Not Able to Access WP-Admin](http://www.wpbeginner.com/plugins/how-to-deactivate-all-plugins-when-not-able-to-access-wp-admin/)
   and (2) switch WordPress debug mode to ‘on’ ([procedure](https://codex.wordpress.org/WP_DEBUG))
 * I entered my site again: (mydomain)/wp-admin. And I see on the Plugin screen:
 * > The following required plugins are currently inactive: Odio Essentials and 
   > Visual Content Composer.
 * So, I activate the two required plugins. (I don’t activate other plugins yet).
 * I activate Polylang, and this is the error string as a result of the debugging:
 * > Fatal error: Call to a member function get_default_language() on a non-object
   > in (mydomain)/public_html/wp-content/themes/odio/functions.php on line 11
 * The cause for this error is a WPML ready theme (like Odio) that uses an internal
   WPML function without testing the existence of it.
 * I asked the theme developer to make his theme also ready for Polylang, but there
   is **something you can do to make a WPML ready theme Polylang compatible**. You
   find the solution [here](https://polylang.wordpress.com/2014/05/30/fatal-error-call-to-a-member-function-on-a-non-object-in/).
 * It worked for me. All the luck!
 * [https://wordpress.org/plugins/polylang/](https://wordpress.org/plugins/polylang/)

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## Tags

 * [conflict](https://wordpress.org/support/topic-tag/conflict/)
 * [language](https://wordpress.org/support/topic-tag/language/)
 * [Localization](https://wordpress.org/support/topic-tag/localization/)

 * 0 replies
 * 1 participant
 * Last reply from: [bartbeat](https://wordpress.org/support/users/bartbeat/)
 * Last activity: [10 years, 2 months ago](https://wordpress.org/support/topic/solution-for-server-error-500/)
 * Status: not a support question