diff --git a/htdocs/blockedlog/admin/blockedlog_list.php b/htdocs/blockedlog/admin/blockedlog_list.php
index 4be8dae3391..83985ecdbcd 100644
--- a/htdocs/blockedlog/admin/blockedlog_list.php
+++ b/htdocs/blockedlog/admin/blockedlog_list.php
@@ -312,6 +312,25 @@ if ($withtab) {
 	$param .= '&withtab='.((int) $withtab);
 }
 
+
+// Make some tests on config validity.
+$hmac_encoded_secret_key = $block_static->getEncodedHMACSecretKey();
+if (empty($hmac_encoded_secret_key)) {
+	print '<div class="error">';
+	print 'Error: BLOCKEDLOG_HMAC_KEY was not found. It should have been initialized to a value "BLOCKEDLOG_HMAC_...." during initialization of module BlockedLog or during migration of an old version.';
+	print '</div>';
+}
+// Here we have the obfuscated value of BLOCKEDLOG_HMAC_KEY in $hmac_encoded_secret_key. We need to unobfuscate it.
+$hmac_secret_key = '';
+try {
+	$hmac_secret_key = $block_static->getClearHMACSecretKey($hmac_encoded_secret_key);		// Note: On network trouble, an Exception is thrown to the caller
+} catch (Exception $e) {
+	print '<div class="error">';
+	print $e->getMessage();
+	print '</div>';
+}
+
+
 print '<form method="POST" id="searchFormList" action="'.dolBuildUrl($_SERVER["PHP_SELF"]).'" spellcheck="false">';
 
 if ($optioncss != '') {
diff --git a/htdocs/blockedlog/class/blockedlog.class.php b/htdocs/blockedlog/class/blockedlog.class.php
index e6287c7f6f5..2f3bcf9fd83 100644
--- a/htdocs/blockedlog/class/blockedlog.class.php
+++ b/htdocs/blockedlog/class/blockedlog.class.php
@@ -1610,7 +1610,7 @@ class BlockedLog
 	 */
 	private function buildFinalSignatureHash($clearstring, $format = '')
 	{
-		global $conf, $mysoc;
+		global $mysoc;
 
 		if (empty($format)) {
 			$format = $this->object_format;