Title: Fatal error: Call to undefined function wp_json_encode…
Last modified: August 22, 2016

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# Fatal error: Call to undefined function wp_json_encode…

 *  Resolved [Coolcatillustration](https://wordpress.org/support/users/coolcatillustration/)
 * (@coolcatillustration)
 * [11 years, 3 months ago](https://wordpress.org/support/topic/fatal-error-call-to-undefined-function-wp_json_encode-1/)
 * Hello,
 * I have this error when trying to login on my website:
 * Fatal error: Call to undefined function wp_json_encode() in /websites/123reg/
   LinuxPackage22/co/ol/ca/coolcatillustration.co.uk/public_html/wp-admin/includes/
   misc.php on line 668
 * Im not technically minded and I know it’s something to do with the update being
   incomplete. I read on here I need to do a manual upgrade via my ftp but looks
   a bit complicated. Can someone help me please?
    Im not sure what version of wordpress
   im using either it’s been at least 6 months since my last upgrade.

Viewing 3 replies - 1 through 3 (of 3 total)

 *  Moderator [James Huff](https://wordpress.org/support/users/macmanx/)
 * (@macmanx)
 * [11 years, 3 months ago](https://wordpress.org/support/topic/fatal-error-call-to-undefined-function-wp_json_encode-1/#post-5825411)
 * Try [manually resetting your plugins](https://codex.wordpress.org/FAQ_Troubleshooting#How_to_deactivate_all_plugins_when_not_able_to_access_the_administrative_menus.3F)(
   no Dashboard access required). If that resolves the issue, reactivate each one
   individually until you find the cause.
 * If that does not resolve the issue, access your server via [FTP or SFTP](https://codex.wordpress.org/FTP_Clients),
   navigate to `/wp-content/themes/` and rename the directory of your currently 
   active theme. This will force the default theme to activate and hopefully rule-
   out a theme-specific issue (theme functions can interfere like plugins).
 *  Thread Starter [Coolcatillustration](https://wordpress.org/support/users/coolcatillustration/)
 * (@coolcatillustration)
 * [11 years, 3 months ago](https://wordpress.org/support/topic/fatal-error-call-to-undefined-function-wp_json_encode-1/#post-5825608)
 * Hello James,
 * I did exactly what you said and hey presto!! It now works. Thanks for your advice.
   Much appreciated.
 * Regards
    Lisa
 *  Moderator [James Huff](https://wordpress.org/support/users/macmanx/)
 * (@macmanx)
 * [11 years, 3 months ago](https://wordpress.org/support/topic/fatal-error-call-to-undefined-function-wp_json_encode-1/#post-5825620)
 * You’re welcome!

Viewing 3 replies - 1 through 3 (of 3 total)

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## Tags

 * [fatal error](https://wordpress.org/support/topic-tag/fatal-error/)
 * [undefined function](https://wordpress.org/support/topic-tag/undefined-function/)

 * In: [Fixing WordPress](https://wordpress.org/support/forum/how-to-and-troubleshooting/)
 * 3 replies
 * 2 participants
 * Last reply from: [James Huff](https://wordpress.org/support/users/macmanx/)
 * Last activity: [11 years, 3 months ago](https://wordpress.org/support/topic/fatal-error-call-to-undefined-function-wp_json_encode-1/#post-5825620)
 * Status: resolved

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