diff --git a/doc/api/tls.md b/doc/api/tls.md
index 11c6bb953d2f0b..57705cad07ad98 100644
--- a/doc/api/tls.md
+++ b/doc/api/tls.md
@@ -373,7 +373,7 @@ are not enabled by default since they offer less security.
 ## X509 Certificate Error codes
 
 Multiple functions can fail due to certificate errors that are reported by
-OpenSSL. In such a case, the function provides a {Error} via its callback that
+OpenSSL. In such a case, the function provides an {Error} via its callback that
 has the property `code` which can take one of the following values:
 
 <!--