diff --git a/ChangeLog.txt b/ChangeLog.txt
index 419b2d4e..38bb4a0b 100644
--- a/ChangeLog.txt
+++ b/ChangeLog.txt
@@ -7,6 +7,8 @@
 - Fix password length not being passed to MOSQ_EVT_BASIC_AUTH events.
   Closes #3490.
 - Fix incorrect maximum-packet-size restriction. Closes #3503.
+- Fix will messages being incorrectly delayed if a client set
+  session-expiry-interval=0 when using will-delay-interval>0. Closes #3505.
 
 # Common lib:
 - Fix potential crash if reading a file in restricted mode and the group id
diff --git a/src/context.c b/src/context.c
index 6b397d47..bb3dae96 100644
--- a/src/context.c
+++ b/src/context.c
@@ -216,7 +216,7 @@ void context__cleanup(struct mosquitto *context, bool force_free)
 void context__send_will(struct mosquitto *ctxt)
 {
 	if(ctxt->state != mosq_cs_disconnecting && ctxt->will){
-		if(ctxt->will_delay_interval > 0){
+		if(ctxt->session_expiry_interval > 0 && ctxt->will_delay_interval > 0){
 			will_delay__add(ctxt);
 			return;
 		}
diff --git a/test/broker/07-will-delay-reconnect.py b/test/broker/07-will-delay-reconnect.py
index e0355a48..504c074e 100755
--- a/test/broker/07-will-delay-reconnect.py
+++ b/test/broker/07-will-delay-reconnect.py
@@ -14,12 +14,13 @@ def do_test(start_broker):
     connect1_packet = mosq_test.gen_connect("will-delay-reconnect-test", proto_ver=5)
     connack1_packet = mosq_test.gen_connack(rc=0, proto_ver=5)
 
-    props = mqtt5_props.gen_uint32_prop(mqtt5_props.WILL_DELAY_INTERVAL, 3)
-    connect2a_packet = mosq_test.gen_connect("will-delay-reconnect-helper", proto_ver=5, will_topic="will/delay/reconnect/test", will_payload=b"will delay", will_properties=props, clean_session=False)
+    props = mqtt5_props.gen_uint32_prop(mqtt5_props.SESSION_EXPIRY_INTERVAL, 60)
+    will_props = mqtt5_props.gen_uint32_prop(mqtt5_props.WILL_DELAY_INTERVAL, 3)
+    connect2a_packet = mosq_test.gen_connect("will-delay-reconnect-helper", proto_ver=5, will_topic="will/delay/reconnect/test", will_payload=b"will delay", will_properties=will_props, clean_session=False, properties=props)
     connack2a_packet = mosq_test.gen_connack(rc=0, proto_ver=5)
 
-    connect2b_packet = mosq_test.gen_connect("will-delay-reconnect-helper", proto_ver=5, clean_session=True)
-    connack2b_packet = mosq_test.gen_connack(rc=0, proto_ver=5)
+    connect2b_packet = mosq_test.gen_connect("will-delay-reconnect-helper", proto_ver=5, clean_session=False)
+    connack2b_packet = mosq_test.gen_connack(rc=0, flags=1, proto_ver=5)
 
     subscribe_packet = mosq_test.gen_subscribe(mid, "will/delay/reconnect/test", 0, proto_ver=5)
     suback_packet = mosq_test.gen_suback(mid, 0, proto_ver=5)
diff --git a/test/broker/07-will-delay-recover.py b/test/broker/07-will-delay-recover.py
index ffdb9612..7e5c196d 100755
--- a/test/broker/07-will-delay-recover.py
+++ b/test/broker/07-will-delay-recover.py
@@ -27,6 +27,8 @@ def do_test(start_broker, clean_session):
 
     connect2_packet_clear = mosq_test.gen_connect("will-delay-recovery-helper", proto_ver=5)
 
+    will_packet = mosq_test.gen_publish(topic="will/delay/recovery/test", payload="will delay", qos=0, proto_ver=5)
+
     port = mosq_test.get_port()
     if start_broker:
         broker = mosq_test.start_broker(filename=os.path.basename(__file__), port=port)
@@ -43,8 +45,13 @@ def do_test(start_broker, clean_session):
         time.sleep(3)
 
         # The client2 has reconnected within the will delay interval, which has now
-        # passed. We should not have received the will at this point.
-        mosq_test.do_ping(sock1)
+        # passed.
+        if clean_session:
+            # The old session has ended, so we should receive the will
+            mosq_test.expect_packet(sock1, "will", will_packet)
+        else:
+            # We should not have received the will at this point.
+            mosq_test.do_ping(sock1)
         rc = 0
 
         sock1.close()
diff --git a/test/broker/07-will-delay-session-expiry-0.py b/test/broker/07-will-delay-session-expiry-0.py
new file mode 100755
index 00000000..eded4be9
--- /dev/null
+++ b/test/broker/07-will-delay-session-expiry-0.py
@@ -0,0 +1,65 @@
+#!/usr/bin/env python3
+
+# Test whether a client that connects with a will delay that is longer than
+# their session expiry interval has their will published.
+# MQTT 5
+# https://github.com/eclipse/mosquitto/issues/1401
+
+from mosq_test_helper import *
+
+def do_test(start_broker):
+    rc = 1
+
+    mid = 1
+    connect1_packet = mosq_test.gen_connect("will-session-exp", proto_ver=5)
+    connack1_packet = mosq_test.gen_connack(rc=0, proto_ver=5)
+
+    will_props = mqtt5_props.gen_uint32_prop(mqtt5_props.WILL_DELAY_INTERVAL, 60)
+    connect_props = mqtt5_props.gen_uint32_prop(mqtt5_props.SESSION_EXPIRY_INTERVAL, 0)
+
+    connect2_packet = mosq_test.gen_connect("will-session-exp-helper", proto_ver=5, properties=connect_props, will_topic="will/session-expiry/test", will_payload=b"will delay", will_qos=2, will_properties=will_props)
+    connack2_packet = mosq_test.gen_connack(rc=0, proto_ver=5)
+
+    subscribe_packet = mosq_test.gen_subscribe(mid, "will/session-expiry/test", 0, proto_ver=5)
+    suback_packet = mosq_test.gen_suback(mid, 0, proto_ver=5)
+
+    publish_packet = mosq_test.gen_publish("will/session-expiry/test", qos=0, payload="will delay", proto_ver=5)
+
+    port = mosq_test.get_port()
+    if start_broker:
+        broker = mosq_test.start_broker(filename=os.path.basename(__file__), port=port)
+
+    try:
+        sock1 = mosq_test.do_client_connect(connect1_packet, connack1_packet, timeout=5, port=port, connack_error="connack1")
+        mosq_test.do_send_receive(sock1, subscribe_packet, suback_packet, "suback")
+
+        sock2 = mosq_test.do_client_connect(connect2_packet, connack2_packet, timeout=5, port=port, connack_error="connack2")
+        time.sleep(1)
+        sock2.close()
+
+        # Will should be sent immediately due to session-expiry-interval=0. If not, the read will timeout
+        mosq_test.expect_packet(sock1, "publish", publish_packet)
+        rc = 0
+
+        sock1.close()
+    except mosq_test.TestError:
+        pass
+    finally:
+        if start_broker:
+            broker.terminate()
+            if mosq_test.wait_for_subprocess(broker):
+                print("broker not terminated")
+                if rc == 0: rc=1
+            (stdo, stde) = broker.communicate()
+            if rc:
+                print(stde.decode('utf-8'))
+                exit(rc)
+        else:
+            return rc
+
+
+def all_tests(start_broker=False):
+    return do_test(start_broker)
+
+if __name__ == '__main__':
+    all_tests(True)
diff --git a/test/broker/07-will-delay.py b/test/broker/07-will-delay.py
index d1e39828..e148ea1e 100755
--- a/test/broker/07-will-delay.py
+++ b/test/broker/07-will-delay.py
@@ -12,8 +12,9 @@ def do_test(start_broker, clean_session):
     connect1_packet = mosq_test.gen_connect("will-delay-test", proto_ver=5)
     connack1_packet = mosq_test.gen_connack(rc=0, proto_ver=5)
 
-    props = mqtt5_props.gen_uint32_prop(mqtt5_props.WILL_DELAY_INTERVAL, 3)
-    connect2_packet = mosq_test.gen_connect("will-delay-helper", proto_ver=5, will_topic="will/delay/test", will_payload=b"will delay", will_qos=2, will_properties=props, clean_session=clean_session)
+    props = mqtt5_props.gen_uint32_prop(mqtt5_props.SESSION_EXPIRY_INTERVAL, 60)
+    will_props = mqtt5_props.gen_uint32_prop(mqtt5_props.WILL_DELAY_INTERVAL, 3)
+    connect2_packet = mosq_test.gen_connect("will-delay-helper", proto_ver=5, properties=props, will_topic="will/delay/test", will_payload=b"will delay", will_qos=2, will_properties=will_props, clean_session=clean_session)
     connack2_packet = mosq_test.gen_connack(rc=0, proto_ver=5)
 
     subscribe_packet = mosq_test.gen_subscribe(mid, "will/delay/test", 0, proto_ver=5)
diff --git a/test/broker/Makefile b/test/broker/Makefile
index ebdeb0fa..ea353bc6 100644
--- a/test/broker/Makefile
+++ b/test/broker/Makefile
@@ -148,6 +148,7 @@ msg_sequence_test:
 	./07-will-delay-invalid-573191.py
 	./07-will-delay-reconnect.py
 	./07-will-delay-recover.py
+	./07-will-delay-session-expiry-0.py
 	./07-will-delay-session-expiry.py
 	./07-will-delay-session-expiry2.py
 	./07-will-delay.py
diff --git a/test/broker/test.py b/test/broker/test.py
index 02bcae26..4c8003d5 100755
--- a/test/broker/test.py
+++ b/test/broker/test.py
@@ -125,6 +125,7 @@ tests = [
     (1, './07-will-delay-invalid-573191.py'),
     (1, './07-will-delay-reconnect.py'),
     (1, './07-will-delay-recover.py'),
+    (1, './07-will-delay-session-expiry-0.py'),
     (1, './07-will-delay-session-expiry.py'),
     (1, './07-will-delay-session-expiry2.py'),
     (1, './07-will-delay.py'),