Title: invalid function name
Last modified: June 28, 2019

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# invalid function name

 *  Resolved [Janasworld](https://wordpress.org/support/users/janasworld/)
 * (@janasworld)
 * [6 years, 11 months ago](https://wordpress.org/support/topic/invalid-function-name-2/)
 * Hello,
    I get the following error message on my smartphone. The error occurs 
   only mobile, not on laptop or PC. If I disable the plugin, the error is gone.
 * call_user_func_array() expects parameter 1 to be a valid callback, function ‘
   twentyseventeen_header_style’ not found or invalid function name in /wp-includes/
   class-wp-hook.php on line 286
 * The page I need help with: _[[log in](https://login.wordpress.org/?redirect_to=https%3A%2F%2Fwordpress.org%2Fsupport%2Ftopic%2Finvalid-function-name-2%2F%3Foutput_format%3Dmd&locale=en_US)
   to see the link]_

Viewing 8 replies - 1 through 8 (of 8 total)

 *  Plugin Author [Oliver Campion](https://wordpress.org/support/users/domainsupport/)
 * (@domainsupport)
 * [6 years, 11 months ago](https://wordpress.org/support/topic/invalid-function-name-2/#post-11681761)
 * Hello,
 * Thanks for letting us know! Can you please explain when exactly you get this 
   error and if you are using a child theme?
 * Thank you,
 * Oliver
 *  Thread Starter [Janasworld](https://wordpress.org/support/users/janasworld/)
 * (@janasworld)
 * [6 years, 11 months ago](https://wordpress.org/support/topic/invalid-function-name-2/#post-11681803)
 * Open the link in your mobile phone… I get the error only in mobile browser. No,
   Im not using a child theme
 *  Plugin Author [Oliver Campion](https://wordpress.org/support/users/domainsupport/)
 * (@domainsupport)
 * [6 years, 11 months ago](https://wordpress.org/support/topic/invalid-function-name-2/#post-11681868)
 * OK, I can see the problem 🙂
 * Not sure what plugin you are using to display a different theme on mobiles but
   you have one enabled and it’s not allowing your Twenty Seventeen theme from loading
   it’s functions.php which means the function that our plugin uses doesn’t exist
   when you load it on a mobile.
 * Whatever plugin you are using to display a different theme on mobiles isn’t really
   necessary as Twenty Seventeen is a responsive theme that is already mobile friendly.
 * Hope that helps?
 * Oliver
 *  Thread Starter [Janasworld](https://wordpress.org/support/users/janasworld/)
 * (@janasworld)
 * [6 years, 11 months ago](https://wordpress.org/support/topic/invalid-function-name-2/#post-11681950)
 * No, I havent a other mobile plugin… only yours and if I deactivate your plugin,
   the error is gone…
 * My plugins:
    Akismet Anti-Spam AntiVirus Contact Form 7 GDPR Cookie Consent Google
   Fonts Typography Jetpack Mailchimp for WordPress MailChimp Forms Options for 
   Twenty Seventeen Really Simple CAPTCHA
    -  This reply was modified 6 years, 11 months ago by [Janasworld](https://wordpress.org/support/users/janasworld/).
 *  Plugin Author [Oliver Campion](https://wordpress.org/support/users/domainsupport/)
 * (@domainsupport)
 * [6 years, 11 months ago](https://wordpress.org/support/topic/invalid-function-name-2/#post-11681972)
 * Please turn off Jetpack Mobile Theme.
 * Thank you,
 * Oliver
 *  Thread Starter [Janasworld](https://wordpress.org/support/users/janasworld/)
 * (@janasworld)
 * [6 years, 11 months ago](https://wordpress.org/support/topic/invalid-function-name-2/#post-11681989)
 * Super, its gone!!!
    Thank you so much!
 *  Plugin Author [Oliver Campion](https://wordpress.org/support/users/domainsupport/)
 * (@domainsupport)
 * [6 years, 11 months ago](https://wordpress.org/support/topic/invalid-function-name-2/#post-11681995)
 * No problem. I have put this on my “to do” list to make sure the plugin checks
   that the function exists before running in future.
 * Oliver
 *  Plugin Author [Oliver Campion](https://wordpress.org/support/users/domainsupport/)
 * (@domainsupport)
 * [6 years, 11 months ago](https://wordpress.org/support/topic/invalid-function-name-2/#post-11700271)
 * Just to update this thread, we have implemented a check to make sure the them
   function exists before using it so this issue should now not present itself again.
 * Oliver

Viewing 8 replies - 1 through 8 (of 8 total)

The topic ‘invalid function name’ is closed to new replies.

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## Tags

 * [jetpack mobile theme](https://wordpress.org/support/topic-tag/jetpack-mobile-theme/)

 * 8 replies
 * 2 participants
 * Last reply from: [Oliver Campion](https://wordpress.org/support/users/domainsupport/)
 * Last activity: [6 years, 11 months ago](https://wordpress.org/support/topic/invalid-function-name-2/#post-11700271)
 * Status: resolved