1 files changed, 2 insertions, 1 deletions
diff --git a/synapse/storage/databases/main/registration.py b/synapse/storage/databases/main/registration.py
index 8478463a2a..0e8c168667 100644
--- a/synapse/storage/databases/main/registration.py
+++ b/synapse/storage/databases/main/registration.py
@@ -1198,8 +1198,9 @@ class RegistrationWorkerStore(CacheInvalidationWorkerStore):
         expiration_ts = now_ms + self._account_validity_period
 
         if use_delta:
+            assert self._account_validity_startup_job_max_delta is not None
             expiration_ts = random.randrange(
-                expiration_ts - self._account_validity_startup_job_max_delta,
+                int(expiration_ts - self._account_validity_startup_job_max_delta),
                 expiration_ts,
             )