diff --git a/src/palace/manager/api/authentication/basic.py b/src/palace/manager/api/authentication/basic.py
index 81a1753c2..42274c21e 100644
--- a/src/palace/manager/api/authentication/basic.py
+++ b/src/palace/manager/api/authentication/basic.py
@@ -41,7 +41,7 @@
 from palace.manager.sqlalchemy.model.patron import Patron
 from palace.manager.sqlalchemy.util import get_one
 from palace.manager.util.log import elapsed_time_logging
-from palace.manager.util.problem_detail import ProblemDetail
+from palace.manager.util.problem_detail import ProblemDetail, ProblemDetailException
 
 
 class LibraryIdentifierRestriction(Enum):
@@ -412,28 +412,33 @@ def testing_patron_or_bust(self, _db: Session) -> tuple[Patron, str | None]:
         if self.test_username is None:
             raise CannotLoadConfiguration("No test patron identifier is configured.")
 
-        patron, password = self.testing_patron(_db)
+        try:
+            patron, password = self.testing_patron(_db)
+        except ProblemDetailException as e:
+            patron = e.problem_detail
+
         if isinstance(patron, Patron):
             return patron, password
 
+        debug_message = None
         if not patron:
             message = (
                 "Remote declined to authenticate the test patron. "
                 "The patron may not exist or its password may be wrong."
             )
         elif isinstance(patron, ProblemDetail):
-            message = (
-                "Test patron lookup returned a problem detail - {}: {} ({})".format(
-                    patron.title, patron.detail, patron.uri
-                )
-            )
+            pd = patron
+            message = f"Test patron lookup returned a problem detail - {pd.title}: {pd.detail} ({pd.uri})"
+            if pd.debug_message:
+                message += f" [{pd.debug_message}]"
+                debug_message = pd.debug_message
         else:
             message = (  # type: ignore[unreachable]
                 "Test patron lookup returned invalid value for patron: {!r}".format(
                     patron
                 )
             )
-        raise IntegrationException(message)
+        raise IntegrationException(message, debug_message=debug_message)
 
     def _run_self_tests(self, _db: Session) -> Generator[SelfTestResult, None, None]:
         """Verify the credentials of the test patron for this integration,
diff --git a/src/palace/manager/api/sip/__init__.py b/src/palace/manager/api/sip/__init__.py
index 19166dd53..794544213 100644
--- a/src/palace/manager/api/sip/__init__.py
+++ b/src/palace/manager/api/sip/__init__.py
@@ -352,6 +352,18 @@ def remote_authenticate(
         self._enforce_patron_location_restriction(info)
         return self.info_to_patrondata(info)
 
+    def _location_mismatch_message(
+        self, patron_location: str | None, library_restriction: str | None = None
+    ) -> str:
+        library_restriction = library_restriction or self.patron_location_restriction
+        patron_location = (
+            f"'{patron_location}'" if patron_location is not None else "(missing)"
+        )
+        return (
+            f"Patron location ({patron_location}) does not match "
+            f"library location restriction ('{library_restriction}')."
+        )
+
     def _enforce_patron_location_restriction(
         self, info: dict[str, Any] | ProblemDetail
     ) -> None:
@@ -365,9 +377,13 @@ def _enforce_patron_location_restriction(
         if (
             not isinstance(info, ProblemDetail)
             and self.patron_location_restriction is not None
-            and info.get("permanent_location") != self.patron_location_restriction
+            and self.patron_location_restriction != info.get("permanent_location")
         ):
-            raise ProblemDetailException(PATRON_OF_ANOTHER_LIBRARY)
+            raise ProblemDetailException(
+                PATRON_OF_ANOTHER_LIBRARY.with_debug(
+                    self._location_mismatch_message(info.get("permanent_location"))
+                )
+            )
 
     def _run_self_tests(self, _db):
         def makeConnection(sip):
diff --git a/tests/manager/api/sip/test_authentication_provider.py b/tests/manager/api/sip/test_authentication_provider.py
index 0daf048c6..f0a932beb 100644
--- a/tests/manager/api/sip/test_authentication_provider.py
+++ b/tests/manager/api/sip/test_authentication_provider.py
@@ -346,8 +346,9 @@ def test_remote_authenticate_location_restriction(
         create_library_settings: Callable[..., SIP2Settings],
     ):
         # This patron authentication library instance is configured with "TestLoc".
+        library_restriction = "TestLoc"
         library_settings = create_library_settings(
-            patron_location_restriction="TestLoc"
+            patron_location_restriction=library_restriction
         )
         provider = create_provider(library_settings=library_settings)
         client = cast(MockSIPClient, provider.client)
@@ -364,14 +365,22 @@ def test_remote_authenticate_location_restriction(
         client.queue_response(self.end_session_response)
         with pytest.raises(ProblemDetailException) as exc:
             provider.remote_authenticate("user", "pass")
-        assert exc.value.problem_detail == PATRON_OF_ANOTHER_LIBRARY
+        debug_message = provider._location_mismatch_message(None, library_restriction)
+        assert exc.value.problem_detail == PATRON_OF_ANOTHER_LIBRARY.with_debug(
+            debug_message
+        )
 
         # This patron has the WRONG location.
         client.queue_response(self.evergreen_patron_with_wrong_loc)
         client.queue_response(self.end_session_response)
         with pytest.raises(ProblemDetailException) as exc:
             provider.remote_authenticate("user", "pass")
-        assert exc.value.problem_detail == PATRON_OF_ANOTHER_LIBRARY
+        debug_message = provider._location_mismatch_message(
+            "OtherLoc", library_restriction
+        )
+        assert exc.value.problem_detail == PATRON_OF_ANOTHER_LIBRARY.with_debug(
+            debug_message
+        )
 
     def test_encoding(
         self,