Support » Plugin: Contact Form 7 » JSON error when submitting form

  • Resolved ScalarEnt


    When submitting any form from the website, it now just displays a JSON error below the button and nothing is sent.

    Error message is different in different browsers:

    Chrome 59.0.3071.115 – “Unexpected token < in JSON at position 0”

    FF 54.0.1 – “JSON.parse: unexpected character at line 1 column 1 of the JSON data”

    IE 11 – “Invalid character”

    Forms were working fine until now. No updates or changes done on website recently.
    Problem seen initially in WP 4.7.5 – installed 4.8 but same problem.

    Deleted and re-installed plugin (Ver 4.8) but no different.

    Any ideas ?

Viewing 7 replies - 1 through 7 (of 7 total)
  • Plugin Author Takayuki Miyoshi


    What other plugins and theme do you use?

    Hi Takayuki,

    Thanks for your email. Details below:

    WordPress Plugins
    Akismet Anti-Spam – Version 3.3.2 Inactive
    bbPress – Version 2.5.12 Inactive
    Breadcrumb NavXT – Version 5.7.0 Active
    Broken Link Checker – Version 1.11.3 Inactive
    Contact Form 7 – Version 4.8 Active
    Envato WordPress Toolkit – Version 1.7.3 Active
    Google Analytics for WordPress by MonsterInsights – Version 6.2.0 Active
    HTML Page Sitemap – Version 1.3 Active
    Jetpack by – Version 5.0 Inactive
    LayerSlider WP – Version 5.1.1 Active
    P3 (Plugin Performance Profiler) – Version Active
    Really Simple CAPTCHA – Version 2.0 Active
    Revolution Slider – Version 4.6.3 Active
    Shareaholic | share buttons, analytics, related content – Version Active
    Shortcodes Ultimate – Version 4.10.1 Active
    Social Icon Widget – Version 1.0.1 Active
    The Events Calendar – Version 4.5.7 Active
    UpdraftPlus – Backup/Restore – Version 1.13.4 Active
    Wordfence Security – Version 6.3.12 Active
    WP-Cron Control – Version 0.7.1 Inactive
    WP Crontrol – Version 1.5 Inactive
    Yoast SEO – Version 4.9 Active

    Theme: Child theme based on Stability Version 1.0.0


    Plugin Author Takayuki Miyoshi


    Try switching to the default theme and deactivating all the plugins except Contact Form 7, Really Simple CAPTCHA, and Yoast SEO.

    Hi Takayuki,

    I have done as you suggested and the problem appears to be with the Stability theme. I have checked and there do not appear to be any newer versions.


    Hi Takayuki,

    This issue is not resolved. The theme has not been changed but this problem just started occurring recently.

    Does your plugin use JSON that might give the error ?

    FF 54.0.1 – “JSON.parse: unexpected character at line 1 column 1 of the JSON data”

    Is there any way of tracing where the problem lies ?

    BTW – I found a newer version of the stability theme (3.0.6) and this exhibits exactly the same problem.

    How is this resolved? No answers apart from the basic ‘turn off your plugins one by one’

    Having spent many wasted hours on the same issue i eventually narrowed it down to hosting. Ask them about mod_rewrite at the server level and explain your problem.
    I made a test site on a server that i know doesn’t balk at CF7 with the exact same setup and it ‘just worked’.

Viewing 7 replies - 1 through 7 (of 7 total)
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