Frequently asked questions
Sometimes, you may see a "server error" message instead of your website. Below, you can see and overview of the most common errors and their most likely causes.
- Blank page, no error
- 403 Forbidden
- 404 Not Found
- 500 Internal Server Error
- 500 PHP/Programming error, bad file/directory permissions or invalid site software configuration
- 503 Backend Fetch Failed
- 503 Service Unavailable
Blank page, no error
Some browsers try to be extra "user friendly" by hiding error messages, and instead displaying a blank page. The real error can be any of the ones listed below, but most commonly one of the "500" errors.
Occasionally, your CMS (e.g. Drupal, Joomla! or WordPress) create a blank page when they fail to create content. This may be caused by a faulty plugin (component, module) or template/theme.
A third possibility is that you have accidentally edited a PHP file with software that saves the file in an invalid format. One example is Dreamweaver, which adds an invisible mark (BOM, the byte order mark) at the beginning of each file, when Dreamweaver thinks the file contains characters not found in US-ASCII. In these cases, the file must be recreated from scratch in US-ASCII.
This error message can appear for a variety of reasons:
- There is no index file in your web ("www") directory/folder. You should always have a file named "index.html", "index.htm", "index.shtml", "index.cgi" or "index.php" (only lowercase letters) in your web directory.
- This message may also appear if you have set up a WWW forwarding to index.html. Note that WWW forwardings within your web hotel should refer to directories, not to file names.
- The directory/folder or file is missing the correct file permissions.
- You have installed a
.htaccess, which is limiting access, e.g. by denying access to file listings, or
.htaccesshas the wrong permissions.
- PHP software attempts to open files outside your web area, which it does not have access to (outside
open_basedir). This can be a configuration or programming error in your software.
- There are too many concurrent accesses from your IP address to the webpage, which triggers a self defense mechanism in the web server. Wait for 10 seconds and try again.
404 Not Found
Your web browser could not find the web page. This is not a server problem.
This message may appear if you've accidentally entered the wrong address, or if the link you followed was wrong.
500 Internal Server Error
This error message is misleading, since it rarely indicates an internal server error. For newer webservers (supporting PHP 5.5) the error message is therefore dependent on whether it is PHP or another file type:
500 PHP error, bad file/directory permissions or invalid site software configuration
500 Programming error, bad file/directory permissions or invalid site software configuration
The message may be caused by:
- incorrect file and/or directory permissions
- invalid configuration in
- a programming error, e.g. crashes, uses too much memory, or too long time
- a missing file, which is attempted loaded by a
require()statement, or similar
- full webhotel (all available space used)
- compromised webhotel due to vulnerable software, e.g. out-dated Joomla, JCE, WordPress, Drupal, etc.
This problem can be solved by those who made or is maintaining the web pages.
503 Backend Fetch Failed
503 Service Unavailable
This error message occurs under two different circumstances:
- Below the error message, there is a text starting with "XID:" followed by a long number. This happens when Varnish cannot fetch the website, see below for more information.
- No "XID": There are too many concurrent accesses from your IP address to the webpage, which triggers a self defense mechanism in the web server. Wait for 10 seconds and try again.
Varnish - XID: 1234567890
Varnish cannot fetch the website when the connection gets interrupted. Common causes for this problem are:
- The website takes too long to load, and therefore crashes
- The website tries to use too much meory, and crashes
- The website uses too much resources, and new requests cannot be served
These problems are usually caused by programming errors, or that the website is simply using too much resources.