Moderator
James Huff
(@macmanx)
Volunteer Moderator
Internal server errors (error 500) are often caused by plugin or theme function conflicts, so if you have access to your admin panel, try deactivating all plugins. If you don’t have access to your admin panel, try manually resetting your plugins. If that resolves the issue, reactivate each one individually until you find the cause.
If that does not resolve the issue, try switching to the Default theme (WordPress 1.5 – 2.9.2) or the Twenty Ten theme (WordPress 3.0 and higher) to rule-out a theme-specific issue. If you don’t have access to your admin panel, access your server via FTP or SFTP, navigate to /wp-content/themes/ and rename the directory of your currently active theme. This will force the Default theme (WordPress 1.5 – 2.9.2) or the Twenty Ten theme (WordPress 3.0 and higher) to activate and hopefully rule-out a theme-specific issue.
If that does not resolve the issue, it’s possible that a .htaccess rule could be the source of the problem. To check for this, access your server via FTP or SFTP and rename the .htaccess file. If you can’t find a .htaccess file, make sure that you have set your FTP or SFTP client to view invisible files.
If you weren’t able to resolve the issue by either resetting your plugins and theme or renaming your .htaccess file, we may be able to help, but we’ll need a more detailed error message. Internal server errors are usually described in more detail in the server error log. If you have access to your server error log, generate the error again, note the date and time, then immediately check your server error log for any errors that occurred during that time period. If you don’t have access to your server error log, ask your hosting provider to look for you.
Hi James,
Okay, I had attempted to be explicit. Let me try again.
Plugin conflicts: As I said above, I manually reset all my plugins without an impact. Just to be clear: I did exactly what those instructions called for. (In fact, the codex page isn’t complete; it doesn’t mention mu-plugins.)
Theme conflicts: Sorry, I failed to mention this. Yes, disabling all custom themes results in the same issue.
.htaccess: I’m running nginx, not Apache, so that of course means this advice isn’t relevant. That said, without changing nginx’s directives, this was working on 3.0.3. Unless you know of some change in 3.0.4 that would cause a need for changed rewrites?
Detailed error message: here’s the complete error message I’m currently getting if I call wp-admin.
^X2011/01/02 11:40:40 [error] 8627#0: *21240 FastCGI sent in stderr: "PHP Fatal error: Call to undefined function set_screen_options() in /home/noisepages/www/wp-admin/admin.php on line 66" while reading response header from upstream, client: 66.65.40.169, server: noisepages.com, request: "GET /wp-admin/ HTTP/1.1", upstream: "fastcgi://unix:/dev/shm/php-fastcgi.sock:", host: "noisepages.com"
Note that that error message remains even with all themes and plugins disabled.
What would cause WP to fail to load core functions?
I’ll continue to investigate; thanks for your help.
Ha! Okay…
So, I recalled that I had enabled query caching. reset query cache did the trick. Makes perfect sense … the cache was causing a mix of the functions for the two versions of WordPress.
It may be worth adding this note to the codex somewhere as part of the upgrade procedure. (I’ve found query caching has dramatically improved performance.)
I was mistaken; clearing the query cache appeared to solve the problem but it recurred. Now, doing the same has no effect.
I’m temporarily leaving this post as unresolved, but I’m no longer convinced that this is related to the original query, which was upgrade-related.
Therefore, starting a new thread since I’m now tracking another problem –
http://wordpress.org/support/topic/caching-problem-wp_cache_init-error-blank-screen?replies=1#post-1865240
That’s not a double post; it does appear to be another issue. If that’s correct, I’ll mark this resolved.
This issue is resolved. The issue was not directly with the 3.0.4 update, but with APC compatibility.
I will investigate if there was a change to WP files that caused the failure, and open a ticket if so (or at least fully document which combination works)
After a search line by line inside the .htaccess file by the method try and error, commenting and uncommenting the lines.
I can say this 4 lines are my error 500
#On
#RewriteBase /
#RewriteRule ^images/(.*)\.png$ /wp-content/plugins/anyfont/img.php [L]
#</IfModule>
The 4 lines are commented as I have them now to avoid the problem.
Seems to me plugin anyfont is causing the problem in some way.
For my is the end of the way cos im not a coder.
Sorry for the very bad english.
Could someone please explain to me how to fix this? I am having the same problem. I don’t have any idea what “APC” compatibility is. My posts were there, and then they weren’t. I was switching themes. I switched back, and then went to default, and my posts were gone. Instead, I get an error code and sometimes, depending on the theme, a list of recent posts. I can get to the posts if I click on them but the home page is ruined. Changing themes and shutting off plugins did not help. Is this the 3.0.4 upgrade?
