diff --git a/.envs/.ci/.django b/.envs/.ci/.django
index 833bb7ec7..bec17501b 100644
--- a/.envs/.ci/.django
+++ b/.envs/.ci/.django
@@ -23,5 +23,6 @@ DEFAULT_PROCESSING_SERVICE_ENDPOINT=http://ml_backend:2000
 # RabbitMQ
 # ------------------------------------------------------------------------------
 CELERY_BROKER_URL=amqp://rabbituser:rabbitpass@rabbitmq:5672/
+CELERY_RESULT_BACKEND=rpc:// # Use RabbitMQ for results backend
 RABBITMQ_DEFAULT_USER=rabbituser
 RABBITMQ_DEFAULT_PASS=rabbitpass
diff --git a/.envs/.local/.django b/.envs/.local/.django
index 59586664e..e646e46eb 100644
--- a/.envs/.local/.django
+++ b/.envs/.local/.django
@@ -18,6 +18,7 @@ CELERY_FLOWER_PASSWORD=BEQgmCtgyrFieKNoGTsux9YIye0I7P5Q7vEgfJD2C4jxmtHDetFaE2jhS
 
 # RabbitMQ
 CELERY_BROKER_URL=amqp://rabbituser:rabbitpass@rabbitmq:5672/
+CELERY_RESULT_BACKEND=rpc:// # Use RabbitMQ for results backend
 RABBITMQ_DEFAULT_USER=rabbituser
 RABBITMQ_DEFAULT_PASS=rabbitpass
 
diff --git a/config/settings/base.py b/config/settings/base.py
index 95845d034..03124d41a 100644
--- a/config/settings/base.py
+++ b/config/settings/base.py
@@ -305,7 +305,8 @@
 # https://docs.celeryq.dev/en/stable/userguide/configuration.html#std:setting-broker_url
 CELERY_BROKER_URL = env("CELERY_BROKER_URL")
 # https://docs.celeryq.dev/en/stable/userguide/configuration.html#std:setting-result_backend
-CELERY_RESULT_BACKEND = env("CELERY_RESULT_BACKEND", default=env("REDIS_URL", default=None))
+# "rpc://" means use RabbitMQ for results backend by default
+CELERY_RESULT_BACKEND = env("CELERY_RESULT_BACKEND", default="rpc://")  # type: ignore[no-untyped-call]
 # https://docs.celeryq.dev/en/stable/userguide/configuration.html#result-extended
 CELERY_RESULT_EXTENDED = True
 # https://docs.celeryq.dev/en/stable/userguide/configuration.html#result-backend-always-retry
@@ -334,7 +335,8 @@
 # https://docs.celeryq.dev/en/stable/userguide/configuration.html#std-setting-task_send_sent_event
 CELERY_TASK_SEND_SENT_EVENT = True
 
-# Health checking and retries, specific to Redis
+# Health checking and retries if using Redis as results backend
+# https://docs.celeryq.dev/en/stable/userguide/configuration.html#redis
 CELERY_REDIS_MAX_CONNECTIONS = 50  # Total connection pool limit for results backend
 CELERY_REDIS_SOCKET_TIMEOUT = 120  # Match Redis timeout
 CELERY_REDIS_SOCKET_KEEPALIVE = True
@@ -346,15 +348,19 @@
 CELERY_WORKER_PREFETCH_MULTIPLIER = 1
 CELERY_WORKER_ENABLE_PREFETCH_COUNT_REDUCTION = True
 
+# Cancel & return to queue if connection is lost
+# https://docs.celeryq.dev/en/latest/userguide/configuration.html#worker-cancel-long-running-tasks-on-connection-loss
+CELERY_WORKER_CANCEL_LONG_RUNNING_TASKS_ON_CONNECTION_LOSS = True
+
 # RabbitMQ broker connection settings
 # These settings improve reliability for long-running workers with intermittent network issues
 CELERY_BROKER_TRANSPORT_OPTIONS = {
     "socket_timeout": 120,  # Socket read/write timeout (seconds)
-    "socket_connect_timeout": 30,  # Max time to establish connection (seconds)
+    "socket_connect_timeout": 40,  # Max time to establish connection (seconds)
     "socket_keepalive": True,  # Enable TCP keepalive probes
     "retry_on_timeout": True,  # Retry operations on timeout
     "max_connections": 20,  # Per-process connection pool limit
-    "heartbeat": 60,  # RabbitMQ heartbeat interval (seconds) - detects broken connections
+    "heartbeat": 30,  # RabbitMQ heartbeat interval (seconds) - detects broken connections
 }
 
 # Broker connection retry settings