diff --git a/mod/lti/locallib.php b/mod/lti/locallib.php
index 7668e676631..b0e05eba707 100644
--- a/mod/lti/locallib.php
+++ b/mod/lti/locallib.php
@@ -4392,6 +4392,13 @@ function lti_load_cartridge($url, $map, $propertiesmap = array()) {
     $curl = new curl();
     $response = $curl->get($url);
 
+    // Got a completely empty response (real or error), cannot process this with
+    // DOMDocument::loadXML() because it errors with ValueError. So let's throw
+    // the moodle_exception before waiting to examine the errors later.
+    if (trim($response) === '') {
+        throw new moodle_exception('errorreadingfile', '', '', $url);
+    }
+
     // TODO MDL-46023 Replace this code with a call to the new library.
     $origerrors = libxml_use_internal_errors(true);
     $origentity = lti_libxml_disable_entity_loader(true);