diff --git a/main.go b/main.go
index 74a0470..75b8a23 100644
--- a/main.go
+++ b/main.go
@@ -390,7 +390,12 @@ func populateSubmission(submissionURL string, listPath *paths.Path, accessList [
 
 		normalizedListURLObject := normalizeURL(listURLObject)
 		if normalizedListURLObject.String() == normalizedURLObject.String() {
-			submission.Error = "Submission URL is already in the Library Manager index."
+			normalizedSubmissionURLObject := normalizeURL(submissionURLObject)
+			if normalizedURLObject.String() == normalizedSubmissionURLObject.String() {
+				submission.Error = "Submission URL is already in the Library Manager index."
+			} else {
+				submission.Error = fmt.Sprintf("Resolved URL %s is already in the Library Manager index.", normalizedURLObject.String())
+			}
 			return submission, "", true
 		}
 	}
diff --git a/tests/test_all.py b/tests/test_all.py
index 70668f1..039c073 100644
--- a/tests/test_all.py
+++ b/tests/test_all.py
@@ -253,6 +253,27 @@
             "",
             "http://downloads.arduino.cc/libraries/logs/github.com/arduino-libraries/Servo/",
         ),
+        (
+            "resolved-already-in-library-manager",
+            "FooUser",
+            "",
+            "submission",
+            "",
+            [
+                {
+                    "submissionURL": "https://github.com/arduino-org/WiFi_for_UNOWiFi_rev1",
+                    "normalizedURL": "https://github.com/arduino-libraries/WiFi_for_UNOWiFi_rev1.git",
+                    "repositoryName": "WiFi_for_UNOWiFi_rev1",
+                    "name": "",
+                    "official": False,
+                    "tag": "",
+                    "error": "Resolved URL https://github.com/arduino-libraries/WiFi_for_UNOWiFi_rev1.git is already in"
+                    " the Library Manager index.",
+                }
+            ],
+            "",
+            "http://downloads.arduino.cc/libraries/logs/github.com/arduino-libraries/WiFi_for_UNOWiFi_rev1/",
+        ),
         (
             "type-arduino",
             "FooUser",
diff --git a/tests/testdata/resolved-already-in-library-manager/.github/workflows/assets/accesslist.yml b/tests/testdata/resolved-already-in-library-manager/.github/workflows/assets/accesslist.yml
new file mode 100644
index 0000000..fe51488
--- /dev/null
+++ b/tests/testdata/resolved-already-in-library-manager/.github/workflows/assets/accesslist.yml
@@ -0,0 +1 @@
+[]
diff --git a/tests/testdata/resolved-already-in-library-manager/diff.txt b/tests/testdata/resolved-already-in-library-manager/diff.txt
new file mode 100644
index 0000000..656f837
--- /dev/null
+++ b/tests/testdata/resolved-already-in-library-manager/diff.txt
@@ -0,0 +1,8 @@
+diff --git a/repositories.txt b/repositories.txt
+index c080a7a..1194257 100644
+--- a/repositories.txt
++++ b/repositories.txt
+@@ -1,2 +1,3 @@
++https://github.com/arduino-org/WiFi_for_UNOWiFi_rev1
+ https://github.com/arduino-libraries/WiFi_for_UNOWiFi_rev1
+ https://github.com/arduino-libraries/Stepper
diff --git a/tests/testdata/resolved-already-in-library-manager/repositories.txt b/tests/testdata/resolved-already-in-library-manager/repositories.txt
new file mode 100644
index 0000000..7291399
--- /dev/null
+++ b/tests/testdata/resolved-already-in-library-manager/repositories.txt
@@ -0,0 +1,2 @@
+https://github.com/arduino-libraries/WiFi_for_UNOWiFi_rev1
+https://github.com/arduino-libraries/Stepper