diff --git a/certbot/CHANGELOG.md b/certbot/CHANGELOG.md
index 8df29801d..0a5849d82 100644
--- a/certbot/CHANGELOG.md
+++ b/certbot/CHANGELOG.md
@@ -20,6 +20,8 @@ Certbot adheres to [Semantic Versioning](https://semver.org/).
 
 * Fixed an issue on Windows where the `web.config` created by Certbot would sometimes
   conflict with preexisting configurations (#9088).
+* Fixed an issue on Windows where the `webroot` plugin would crash when multiple domains
+  had the same webroot. This affected Certbot 1.21.0.
 
 More details about these changes can be found on our GitHub repo.
 
diff --git a/certbot/certbot/_internal/plugins/webroot.py b/certbot/certbot/_internal/plugins/webroot.py
index 81f46b204..1a4892ac9 100644
--- a/certbot/certbot/_internal/plugins/webroot.py
+++ b/certbot/certbot/_internal/plugins/webroot.py
@@ -221,7 +221,7 @@ to serve all files under specified web root ({0})."""
                 if os.path.exists(web_config_path):
                     logger.info("A web.config file has not been created in "
                                 "%s because another one already exists.", self.full_roots[name])
-                    return
+                    continue
                 logger.info("Creating a web.config file in %s to allow IIS "
                             "to serve challenge files.", self.full_roots[name])
                 with safe_open(web_config_path, mode="w", chmod=0o644) as web_config:
diff --git a/certbot/tests/plugins/webroot_test.py b/certbot/tests/plugins/webroot_test.py
index 54c51ae1d..d7e961596 100644
--- a/certbot/tests/plugins/webroot_test.py
+++ b/certbot/tests/plugins/webroot_test.py
@@ -115,6 +115,22 @@ class AuthenticatorTest(unittest.TestCase):
         from certbot._internal.plugins.webroot import _WEB_CONFIG_SHA256SUMS
         self.assertTrue(webconfig_hash not in _WEB_CONFIG_SHA256SUMS)
 
+    @unittest.skipIf(filesystem.POSIX_MODE, reason='Test specific to Windows')
+    def test_foreign_webconfig_multiple_domains(self):
+        # Covers bug https://github.com/certbot/certbot/issues/9091
+        achall_2 = achallenges.KeyAuthorizationAnnotatedChallenge(
+            challb=acme_util.chall_to_challb(challenges.HTTP01(token=b"bingo"), "pending"),
+            domain="second-thing.com", account_key=KEY)
+        self.config.webroot_map["second-thing.com"] = self.path
+
+        challenge_path = os.path.join(self.path, ".well-known", "acme-challenge")
+        filesystem.makedirs(challenge_path)
+
+        webconfig_path = os.path.join(challenge_path, "web.config")
+        with open(webconfig_path, "w") as file:
+            file.write("something")
+        self.auth.perform([self.achall, achall_2])
+
     @test_util.patch_display_util()
     def test_webroot_from_list_help_and_cancel(self, mock_get_utility):
         self.config.webroot_path = []