diff --git a/test/test_acme-http-challenge-location/test_acme-http-challenge-location-disabled.py b/test/test_acme-http-challenge-location/test_acme-http-challenge-location-disabled.py
index ae12fa6..5588167 100644
--- a/test/test_acme-http-challenge-location/test_acme-http-challenge-location-disabled.py
+++ b/test/test_acme-http-challenge-location/test_acme-http-challenge-location-disabled.py
@@ -25,3 +25,10 @@ def test_noredirect_acme_challenge_location_enabled(docker_compose, nginxproxy,
         allow_redirects=False
     )
     assert r.status_code == 200
+
+def test_unknown_domain_acme_challenge_location_disabled(docker_compose, nginxproxy, acme_challenge_path):
+    r = nginxproxy.get(
+        f"http://web-unknown.nginx-proxy.tld/{acme_challenge_path}",
+        allow_redirects=False
+    )
+    assert r.status_code == 503
diff --git a/test/test_acme-http-challenge-location/test_acme-http-challenge-location-enabled-is-default.py b/test/test_acme-http-challenge-location/test_acme-http-challenge-location-enabled-is-default.py
index 88cb07d..80eea97 100644
--- a/test/test_acme-http-challenge-location/test_acme-http-challenge-location-enabled-is-default.py
+++ b/test/test_acme-http-challenge-location/test_acme-http-challenge-location-enabled-is-default.py
@@ -25,3 +25,10 @@ def test_noredirect_acme_challenge_location_disabled(docker_compose, nginxproxy,
         allow_redirects=False
     )
     assert r.status_code == 404
+
+def test_unknown_domain_acme_challenge_location_default_enabled(docker_compose, nginxproxy, acme_challenge_path):
+    r = nginxproxy.get(
+        f"http://web-unknown.nginx-proxy.tld/{acme_challenge_path}",
+        allow_redirects=False
+    )
+    assert r.status_code == 503
diff --git a/test/test_acme-http-challenge-location/test_acme-http-challenge-location-legacy.py b/test/test_acme-http-challenge-location/test_acme-http-challenge-location-legacy.py
index ed9f25a..495ad83 100644
--- a/test/test_acme-http-challenge-location/test_acme-http-challenge-location-legacy.py
+++ b/test/test_acme-http-challenge-location/test_acme-http-challenge-location-legacy.py
@@ -11,3 +11,10 @@ def test_noredirect_acme_challenge_location_legacy(docker_compose, nginxproxy, a
         allow_redirects=False
     )
     assert r.status_code == 404
+
+def test_unknown_domain_acme_challenge_location_legacy(docker_compose, nginxproxy, acme_challenge_path):
+    r = nginxproxy.get(
+        f"http://web-unknown.nginx-proxy.tld/{acme_challenge_path}",
+        allow_redirects=False
+    )
+    assert r.status_code == 503