diff --git a/enrol/lti/ims-blti/OAuthBody.php b/enrol/lti/ims-blti/OAuthBody.php
index be7b7f9b27d..09c92f5a78b 100644
--- a/enrol/lti/ims-blti/OAuthBody.php
+++ b/enrol/lti/ims-blti/OAuthBody.php
@@ -134,11 +134,19 @@ function sendOAuthParamsPOST($method, $endpoint, $oauth_consumer_key, $oauth_con
     $ctx = stream_context_create($params);
     $fp = @fopen($endpoint, 'rb', false, $ctx);
     if (!$fp) {
-        throw new \Exception("Problem with $endpoint, $php_errormsg");
+        $message = "(No error message provided.)";
+        if ($error = error_get_last()) {
+            $message = $error["message"];
+        }
+        throw new \Exception("Problem with $endpoint, $message");
     }
     $response = @stream_get_contents($fp);
     if ($response === false) {
-        throw new \Exception("Problem reading data from $endpoint, $php_errormsg");
+        $message = "(No error message provided.)";
+        if ($error = error_get_last()) {
+            $message = $error["message"];
+        }
+        throw new \Exception("Problem reading data from $endpoint, $message");
     }
     return $response;
 }
diff --git a/enrol/lti/ims-blti/blti_util.php b/enrol/lti/ims-blti/blti_util.php
index 850131fe98c..99c604ba359 100644
--- a/enrol/lti/ims-blti/blti_util.php
+++ b/enrol/lti/ims-blti/blti_util.php
@@ -208,11 +208,19 @@ function do_post_request($url, $data, $optional_headers = null)
   $fp = @fopen($url, 'rb', false, $ctx);
   if (!$fp) {
     echo @stream_get_contents($fp);
-    throw new Exception("Problem with $url, $php_errormsg");
+    $message = "(No error message provided.)";
+    if ($error = error_get_last()) {
+      $message = $error["message"];
+    }
+    throw new Exception("Problem with $url, $message");
   }
   $response = @stream_get_contents($fp);
   if ($response === false) {
-    throw new Exception("Problem reading data from $url, $php_errormsg");
+    $message = "(No error message provided.)";
+    if ($error = error_get_last()) {
+        $message = $error["message"];
+    }
+    throw new Exception("Problem reading data from $url, $message");
   }
   return $response;
 }
diff --git a/enrol/lti/ims-blti/readme_moodle.txt b/enrol/lti/ims-blti/readme_moodle.txt
index debb489c38f..c39dccfe599 100644
--- a/enrol/lti/ims-blti/readme_moodle.txt
+++ b/enrol/lti/ims-blti/readme_moodle.txt
@@ -5,3 +5,4 @@ In future releases we should look into using a supported library.
 
 2022-01-05 - MDL-73502 - Removed get_magic_quotes_gpc() use, was returning false since ages ago.
 2022-01-20 - MDL-73523 - Conditional openssl_free_key() use, deprecated by PHP 8.0
+2022-03-05 - MDL-73520 - replace deprecated php_errormsg with error_get_last(), deprecated by PHP 8.0