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

Problem:
You are encountering an error in your logs indicating that the cache keys 'product_cat' and 'product_tag' are incompatible with prefetching, and the group 'WPML_Slug_Translation_Records::taxonomy' should be added to the list of non-prefetchable groups. You are concerned about the importance of this error and how to resolve it.
Solution:
We have consulted with our second-tier team and discovered that the WPML plugin defines cache groups for various text domains, which might be causing the notices from Object Cache Pro. The current constant used might not support wildcards, unlike the 'WP_REDIS_CONFIG' which does. We recommend defining this in your wp-config.php file:

define('WP_REDIS_CONFIG', [
    'non_prefetchable_groups' => [
        'WPML_Register_String_Filter*',
        'WPML_Slug_Translation_Records*'
    ],
]);

This configuration should address all variations of the cache group names. However, these warnings might be informational and may not require action if your system operates normally. We suggest verifying this with Object Cache Pro support. If this solution does not resolve your issue or seems irrelevant due to updates or differences in your setup, please check related known issues at https://wpml.org/known-issues/, verify the version of the permanent fix, and ensure you have the latest versions of themes and plugins installed. If further assistance is needed, we highly recommend opening a new support ticket with us.

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This topic contains 18 replies, has 0 voices.

Last updated by zakW 3 months, 2 weeks ago.

Assisted by: Bruno Kos.

Author Posts
July 29, 2025 at 2:28 pm #17279347

zakW

H Bruno,

Unfortunately, when I add the code you mentioned, I'm getting the error in the screenshot.

Is this something you are familiar with or something I need to speak with my hosting company?

Kind Regards
Ruben

Screenshot 2025-07-29 151354.png
July 29, 2025 at 2:40 pm #17279542

Bruno Kos
WPML Supporter since 12/2018

Languages: English (English ) German (Deutsch ) French (Français )

Timezone: Europe/Zagreb (GMT+01:00)

The error message you're seeing, "Error establishing a Redis connection", is related to Redis server configuration, which is outside the scope of WPML support. Redis is a caching layer typically managed at the server level.

Since you are using Object Cache Pro, which is a premium Redis object caching plugin, it requires a working Redis server in the background.

I recommend contacting your hosting provider or server administrator to:

* Confirm that the Redis server is running and reachable.
* Ensure the Redis connection details are correctly defined in your `wp-config.php` file under `WP_REDIS_CONFIG`.

For reference, your hosting support can follow this documentation:
hidden link

July 29, 2025 at 3:01 pm #17279580

zakW

Thank you Bruno,

I will follow up with our hosting company to see why this is not working and Im getting that error as I believe Redis should be configured and working.

Regards
Ruben

July 30, 2025 at 7:11 am #17280646

Bruno Kos
WPML Supporter since 12/2018

Languages: English (English ) German (Deutsch ) French (Français )

Timezone: Europe/Zagreb (GMT+01:00)

Hi Ruben,

Thanks for the update.
No problem — just let me know what you hear back from the hosting company. I'm here if you need any help in the meantime.

Best regards,
Bruno

July 30, 2025 at 8:33 am #17280999

zakW

Hi Bruno.

The hosting support helped me add the code you mentioned, and the error is not showing anymore.

Thank you for the help with this.

I know if I need anything else in the future, I can ask.

Kind Regards
Ruben