not a valid JSON response

This thread is resolved. Here is a description of the problem and solution.

Problem:
When the WPML String Translation plugin is activated, the client cannot save edits to pages and posts, receiving a warning that 'The update failed. The response is not a valid JSON response.' Deactivating the plugin resolves the issue.
Solution:
We recommend clearing the server cache as a first step to resolve this issue. If you're experiencing this problem, please try deleting the server cache and check if the issue persists.

If this solution does not resolve the problem or seems irrelevant due to being outdated or not applicable to your case, we highly recommend checking related known issues at https://wpml.org/known-issues/, verifying the version of the permanent fix, and confirming that you have installed the latest versions of themes and plugins. If the issue continues, please do not hesitate to open a new support ticket. For further assistance, you can also visit our support forum at https://wpml.org/forums/forum/english-support/.

This is the technical support forum for WPML - the multilingual WordPress plugin.

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Tagged: Exception

This topic contains 13 replies, has 0 voices.

Last updated by Paola Mendiburu 2 weeks, 4 days ago.

Assisted by: Paola Mendiburu.

Author	Posts
January 14, 2026 at 8:31 am
andreasH-18	When the plugin: WPML String Translation is activated I can not save edits to pages and posts. I get the following warning: The update failed. The response is not a valid JSON response. If I de-activate the plugin then pages and posts save without any issues. Do you have a fix for this problem please?
January 14, 2026 at 11:07 am #17728812
Paola Mendiburu WPML Supporter since 11/2020 Languages: English (English ) Spanish (Español ) Italian (Italiano ) Timezone: Europe/Madrid (GMT+01:00)	Hi there! In order to continue the testing without affecting your site, do you give me permission to download a copy of your site with Duplicator?
January 16, 2026 at 4:48 am #17735679
andreasH-18	I will need to check if that's possible
January 16, 2026 at 2:58 pm #17737488
Paola Mendiburu WPML Supporter since 11/2020 Languages: English (English ) Spanish (Español ) Italian (Italiano ) Timezone: Europe/Madrid (GMT+01:00)	Please let us know if we can download a copy or you can create a staging site.
January 19, 2026 at 8:08 am #17741193
andreasH-18	Yes I have permission for you, please can you do that.
January 20, 2026 at 8:38 am #17744920
Paola Mendiburu WPML Supporter since 11/2020 Languages: English (English ) Spanish (Español ) Italian (Italiano ) Timezone: Europe/Madrid (GMT+01:00)	Hi there! I am not able to login with my user. It seems the user has been deleted. Could you please add the user again so I can download a copy? I have marked next answer as private.
January 21, 2026 at 2:15 pm #17750815
Paola Mendiburu WPML Supporter since 11/2020 Languages: English (English ) Spanish (Español ) Italian (Italiano ) Timezone: Europe/Madrid (GMT+01:00)	Thanks a lot! I was able to download a copy with Duplicator. I will work on local and let you know when I have some news.
January 22, 2026 at 4:42 pm #17754835
Paola Mendiburu WPML Supporter since 11/2020 Languages: English (English ) Spanish (Español ) Italian (Italiano ) Timezone: Europe/Madrid (GMT+01:00)	Hi there! The issue is not happening on the local copy, I am not getting the error. Please try to delete cache from server and let me know if you reproduce it.
January 28, 2026 at 8:29 am #17769683
andreasH-18	Thank you so much for your help with this, we're concluding this is a server issue that is causing the problems.
January 28, 2026 at 8:36 am #17769721
Paola Mendiburu WPML Supporter since 11/2020 Languages: English (English ) Spanish (Español ) Italian (Italiano ) Timezone: Europe/Madrid (GMT+01:00)	Please do not hesitate to contact us if you have any other problem. Have a nice day!
January 29, 2026 at 9:54 am #17772914
andreasH-18	Hi, I have another issue, different website, different issue. Should I open a new ticket or tell you directly here?
January 29, 2026 at 12:26 pm #17773406
Paola Mendiburu WPML Supporter since 11/2020 Languages: English (English ) Spanish (Español ) Italian (Italiano ) Timezone: Europe/Madrid (GMT+01:00)	Yes please, you can create a new ticket so maybe you can have a chat and it is quicker or you can tell me here and I will create a new ticket for you.
February 1, 2026 at 7:10 am #17780825
andreasH-18	Am really happy dealing direct with you. On a different website: hidden link... I go to the Translation Dashboard in the WPML menu, when I click on the Translators tab the site goes to the fatal error warning. Everything else in WPML is working okay. New threads created by Paola Mendiburu and linked to this one are listed below: https://wpml.org/forums/topic/fatal-error-on-translators/
February 2, 2026 at 1:58 pm #17784118
Paola Mendiburu WPML Supporter since 11/2020 Languages: English (English ) Spanish (Español ) Italian (Italiano ) Timezone: Europe/Madrid (GMT+01:00)	Great! I have created a new ticket here: https://wpml.org/forums/topic/fatal-error-on-translators/ You can mark this one as risolved.