diff --git a/certbot/certbot/_internal/auth_handler.py b/certbot/certbot/_internal/auth_handler.py
index 747520a7d..de41f7e4d 100644
--- a/certbot/certbot/_internal/auth_handler.py
+++ b/certbot/certbot/_internal/auth_handler.py
@@ -384,7 +384,8 @@ def challb_to_achall(challb: messages.ChallengeBody, account_key: josepy.JWK,
             challb=challb, domain=domain, account_key=account_key)
     elif isinstance(chall, challenges.DNS):
         return achallenges.DNS(challb=challb, domain=domain)
-    raise errors.Error(f"Received unsupported challenge of type: {chall.typ}")
+    else:
+        return achallenges.Other(challb=challb, domain=domain)
 
 
 def gen_challenge_path(challbs: List[messages.ChallengeBody],
diff --git a/certbot/certbot/achallenges.py b/certbot/certbot/achallenges.py
index 081fa1c46..fb2deaa70 100644
--- a/certbot/certbot/achallenges.py
+++ b/certbot/certbot/achallenges.py
@@ -59,3 +59,9 @@ class DNS(AnnotatedChallenge):
     """Client annotated "dns" ACME challenge."""
     __slots__ = ('challb', 'domain') # pylint: disable=redefined-slots-in-subclass
     acme_type = challenges.DNS
+
+
+class Other(AnnotatedChallenge):
+    """Client annotated ACME challenge of an unknown type."""
+    __slots__ = ('challb', 'domain') # pylint: disable=redefined-slots-in-subclass
+    acme_type = challenges.Challenge