My WordPress site with latest version of WP Discourse is returning on every post under the discourse tab: There was an error returning the category list from Discourse. The logs are full of errors [2025-09-22 00:10:14] comment.ERROR: sync_comments.get_discourse_category {"message":"The categories key was not found in the response from Discourse."} Just for the heck of it, I created a new API key. I have checked all settings 3 times [Screenshot 7] I have a second WordPress site where it is able to get categories from the same discourse server with no problem. What am I missing?

Thank you @angus Good to know about /site.json where I do see all categories. I found the problem! It was totally PEBKAC. In the plugin settings, for Discourse URL, I had entered an http:// url not https:// - note the example below the field perhaps should reflect this. [Screenshot 128] Changing our URL to https://connect.orglobal.org made everything work. I am embarrassed for missing something so obvious. Case closed.

maybe see this post (and topic) [image] Issues with category selection in WP-Discourse WordPress The “There was an error returning the category list from Discourse” error message in your screenshot indicates that there is a problem with the plugin’s configuration. If you go to the WP Discourse Connection settings tab, are you seeing a notice saying that “You are connected to Discourse”? For the API Key field on that page, have you entered an All Users API Key? If not, could you try changing the API Key to an All Users API Key? On Discourse the key should be generated like this: [image] F…

I thought that was the problem as for some reason I had done the one user, but still no difference. Now I found what is more likely the answer, for some reason our server admin is still running a PHP version 7.4, I need to have them bump it.

Nope, PHP version not the issue. Running now PHP 8.3 and I still see on all posts the discourse category error. [Screenshot 70] The log is full of errors: [2025-09-30 00:15:49] comment.ERROR: sync_comments.get_discourse_category {"message":"The categories key was not found in the response from Discourse."} I have remade the API key several times, its granted to an admin user account. The instructions under API key do not match my discourse API options. If I set the option to “All Users” there is no option to set the User, I only see that if I use the option for “Single User” [Screenshot 77] This previously worked fine, but I have been unable for weeks to get the plugin to work. What am I missing?

[image] cogdog: This previously worked fine, but I have been unable for weeks to get the plugin to work. Let’s think about what changed. The plugin hasn’t changed in the past few weeks, so what may have changed to cause this: Did you make any changes to Wordpress? New plugins, new hosting service, enabled cloudflare etc? Did you make any changes to Discourse? Same as above.

@cogdog were you able to resolve your issue? We’re all curious about an update, esp after Angus shared troubleshooting steps.

I got busy and forgot to reply. I cannot be sure since this is a WordPress site for the organization I work for. My colleagues who post there have not made much use of it, so I cannot be sure how long ago when I remember it worked correctly- maybe months. No hosting change or cloudflare use. There has likely been new plugins. No change was made to discourse settings . I activated more logging when I noticed the problem. Is there any other way to test what the discourse response is- as all the logs indicate is” [2025-10-14 00:13:18] comment.ERROR: sync_comments.get_discourse_category {"message":"The categories key was not found in the response from Discourse."} Sorry I cannot be specific, my focus is not on the tech stack, and my server admin is pretty weak on WordPress.

If possible, could you share a link to your wordpress and discourse instances? If that’s not possible, please have a look at the /site.json endpoint of your discourse. For example if you go to meta.discourse.org/site.json you’ll see some JSON that includes a categories list. Essentially that error appears if: Your Discourse instance returns a non-error response; but There’s no categories in your site.json for some reason. The most likely cause of this is still that described in the topic @Lilly linked. If you could try walking through the steps in this topic and check whether you still have a valid connection to your Discourse: [image] Connect WP Discourse to Discourse Administrators After you’ve installed the WP Discourse Plugin you need to connect it to your Discourse. When you’re ready to go, watch this short video, or follow the instructions below. Next Step Once the plugin is connected, head over to the topic describing the feature you want to set up: Publish posts to Discourse Use Discourse for Wordpress Comments Log in to Discourse with Wordpress (DiscourseConnect) Instructions Steps When you’re looking at the Connection tab of the WP Discourse plugin settings,…

Category request errors

Product Support WordPress

Lilly (Lillian ) September 23, 2025, 3:16am 2

maybe see this post (and topic)

Topic		Replies	Views
Issues with category selection in WP-Discourse WordPress	8	2100	April 30, 2020
Category endpoints not working Product Support wordpress , lazy-load-categories	14	486	September 27, 2024
Sync Wordpress and Discourse categories WordPress	4	741	August 24, 2022
Discourse Wordpress Plugin pulling new discourse categories doesn't work WordPress	4	1271	August 9, 2019
There was an error returning the category list from Discourse Product Support wordpress	3	623	May 19, 2023

Category request errors

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