diff --git a/commands.go b/commands.go
index 644f842..2edf61d 100644
--- a/commands.go
+++ b/commands.go
@@ -203,6 +203,8 @@ func add(user *gumble.User, username, url string) {
 				}
 			} else if fmt.Sprint(err) == "video exceeds the maximum allowed duration." {
 				dj.SendPrivateMessage(user, VIDEO_TOO_LONG_MSG)
+			} else if fmt.Sprint(err) == "Invalid API key supplied." {
+				dj.SendPrivateMessage(user, INVALID_API_KEY)
 			} else {
 				dj.SendPrivateMessage(user, INVALID_YOUTUBE_ID_MSG)
 			}
diff --git a/strings.go b/strings.go
index 15402dc..d48e7a7 100644
--- a/strings.go
+++ b/strings.go
@@ -7,6 +7,9 @@
 
 package main
 
+// Message shown to users when the bot has an invalid YouTube API key.
+const INVALID_API_KEY = "MumbleDJ does not have a valid YouTube API key."
+
 // Message shown to users when they do not have permission to execute a command.
 const NO_PERMISSION_MSG = "You do not have permission to execute that command."