I am trying to debug an intermittent 404 issue that has been traced to BBPress. I’ve read several other reports about intermittent 404s and BBPress, but none of them are quite applicable to my situation, so I’m creating a new support topic.

The main page of my website will intermittently load with a 404.The intermittent access issue appears to last between 10 seconds and 3 minutes at a time. When this happens, it’s down for everyone trying to access the site (confirmed while on the phone with hosting service tech support). Other pages on the site appear to load correctly during this time window. Hitting refresh will eventually successfully reload the page correctly.

I am using Query Monitor to examine the rewrite rules. Here are the results when the page is loading incorrectly:

Request	account-2/conscious-business-design-dashboard
Matched Rule	[^/]+/([^/]+)/?$
Matched Query	attachment=conscious-business-design-dashboard
Query String	attachment=conscious-business-design-dashboard
Query Vars	attachment	conscious-business-design-dashboard
comments_per_page	50
name	conscious-business-design-dashboard
order	DESC
posts_per_page	10
update_post_meta_cache	1
update_post_term_cache	1

Here are the results when the page is loading correctly:

Request	account-2/conscious-business-design-dashboard
Matched Rule	(.?.+?)(?:/([0-9]+))?/?$
Matched Query	pagename=account-2%2Fconscious-business-design-dashboard
&page=
Query String	pagename=account-2%2Fconscious-business-design-dashboard
Query Vars	comments_per_page	50
name	conscious-business-design-dashboard
order	DESC
pagename	conscious-business-design-dashboard
posts_per_page	10
update_post_meta_cache	1
update_post_term_cache	1
Queried Object	
Single Page: #225 (WP_Post)

Here is the most relevant query that is being run during the 404:

	SELECT wp_posts.*
FROM wp_posts 
WHERE 1=1 
AND wp_posts.post_name = 'conscious-business-design-dashboard'
AND wp_posts.post_type = 'attachment' 
ORDER BY wp_posts.post_date DESC 

Here is the query run when the page successfully loads:

SELECT wp_posts.*
FROM wp_posts 
WHERE 1=1 
AND (wp_posts.ID = '225')
AND wp_posts.post_type = 'page' 
ORDER BY wp_posts.post_date DESC 

When I look at the BBPress code, I can identify the rewrite rules here:

	// Rewrite rule matches used repeatedly below
		$root_rule    = '/([^/]+)/?$';
		$feed_rule    = '/([^/]+)/' . $feed_slug  . '/?$';
		$edit_rule    = '/([^/]+)/' . $edit_slug  . '/?$';
		$paged_rule   = '/([^/]+)/' . $paged_slug . '/?([0-9]{1,})/?$';

However, all slugs are correctly set in the database, and I can’t figure out how they might be getting corrupted.

Any suggestions for further troubleshooting?

[@casiepa Moderator 8 years, 10 months ago]

Hi,
I must be missing something, but why do you think this is bbPress related ?
Pascal.

[@campbellschool Participant 8 years, 10 months ago]

When BBPress is turned off, the error stops. When it is turned back on, the error starts again.

Also, the BBPress rewrite rules, especially the root rewrite stub, are the only place in the entire code base that I can find the rewrite rule RegEx fragment.

[@laymission Participant 8 years, 7 months ago]

Have you figured this out. I seem to be experiencing quite a similar issue. the website is laymission.net

The 404 errors seem to disappear for a short amount of time when permalinks are re-saved, but it’s only a temporary fix.

If it helps, am using the theme “University” and the backbone to the website is Learndash LMS

Please help.

[@campbellschool Participant 8 years, 7 months ago]

Yes! It turns out it’s a known issue with Learndash. That link goes to a support log-in for their FAQ, which provides a workaround. To be honest, I only found out about this after stopping using LearnDash, because the problem made the site essentially unusable. So I haven’t tested it for myself.

[@laymission Participant 8 years, 7 months ago]

Thanks!

I’ll test these fixes out and see what happens.

[@campbellschool Participant 8 years, 7 months ago]

Great, let me know how they work for you! I hope this saves you some of the misery I went through. 😉