The response is not a valid JSON response.

  • Resolved kierancalv

    (@kierancalv)


    1 month, 4 weeks ago


    After updating AIOSEO to V5 on 3 seperate sites/ servers, saving/updating posts in the block editor started failing with “Updating failed. The response is not a valid JSON response.” This points to something being output before/alongside the REST response body (likely a PHP notice or warning) that breaks JSON parsing.

    Also noted around the same time: the plugin was intermittently calling /wp-json/aioseo/v1/redirects/post/{id}/ and getting a 404, even though Redirects is a Pro-only feature and this site runs the free version. A full plugin reinstall resolved that specific 404, but the JSON error on post update persisted until I reverted to [previous version].

    What I tried:

    • Confirmed base REST API (/wp-json/) responds normally
    • Flushed permalinks
    • Checked for caching interference (ruled out)
    • Reinstalled the plugin fresh (fixed the redirects 404, did not fix the JSON error)
    • Reverting to V4 resolved the JSON error completely

    Thanks for your help

    • This topic was modified 1 month, 4 weeks ago by kierancalv.
Viewing 1 replies (of 1 total)
  • Plugin Support MM Aurangajeb

    (@aurangajeb)

    1 month, 4 weeks ago

    Hi @kierancalv ,

    Thanks for the detailed troubleshooting, that narrowed this down a lot and helped us reproduce it on our end.

    Here’s what’s happening. AIOSEO 5.0 adds a few new columns to the wp_aioseo_posts database table during the update. On your sites that database upgrade didn’t complete, so the plugin keeps trying to use columns that don’t exist. When you save a post, the failed database call prints an error into the reply the block editor is waiting for, and WordPress reports it as “Updating failed. The response is not a valid JSON response.” Rolling back to V4 stops it because V4 never touches those columns.

    We’ve confirmed this and reported it to our developers so 5.0 handles this state safely and the database upgrade can recover on its own.

    Two things you can try right now:

    1. Deactivate and reactivate All in One SEO on one of the affected sites (your settings are kept). Activation re-runs the database upgrade, which should create the missing pieces.
    2. If saving still fails after that, please reach out to us through our Contact Us page at https://aioseo.com/contact/ and mention this thread, and we’ll investigate further and help you recreate the missing database tables.

    If you prefer, staying on V4 until the fix ships is fine.

    Thank you again for bringing this to our attention.

Viewing 1 replies (of 1 total)

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