RSS Feed: “An error has occurred; the feed is probably down. Try again later.”

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WordPress RSS Feed Widget displays the following broad error message if it has problems to init or display a RSS feeds:

An error has occurred; the feed is probably down. Try again later.

This error message can have multiple reasons (search Google). Those reasons are related to the incorporated SimplePie library. One of the main reasons for the display of the error message however is if the ->init() call for the feed object returns false.

The cause of returning false again can have multiple reasons.

One cause I did not find quite documented is the simple fact that the XML, the PCRE or the XMLREADER extension is not loaded (PHP A-Z extension listing). Normally the XML extension should be loaded nowadays, so probably while checking the server configuration it gets overlooked.

A call to phpinfo(INFO_MODULES); will show which extensions are loaded, here is some other rough script for a quick check:

<?php

$extensions = array('xml', 'pcre', 'xmlreader');

function extension_info($name) {
	$ret = new StdClass();
	$ret->name = $ret->name_ = $name;
	$ret->loaded = (int) extension_loaded($name);
	$ret->version = null;
	if ($ret->loaded) {
		$refl = new ReflectionExtension($name);
		$ret->name = $refl->getName();
		$ret->version = $refl->getVersion();
	}
	return $ret;
}

foreach($extensions as $ext) {
	extract((array) extension_info($ext));
	echo 'Name: ', $name, '(', $name_,') <br>', "\n";
	echo 'Version: ', $version, '<br>', "\n";
	echo 'Loaded: ', $loaded, '<br>', "\n";
	echo '<hr>';
}

// phpinfo(INFO_MODULES);

You can find all SimplePie Requirements in the SimplePie Documentation.

Read On: WordPress Technical Installation Checklist

Image Credits: A quote from the Movie Rebecca (1940) directed by Alfred Hitchcock has been used in the picture.

Image may be NSFW.
Clik here to view.

Image may be NSFW.
Clik here to view.