diff --git a/lbry/blockchain/lbrycrd.py b/lbry/blockchain/lbrycrd.py
index 441f8f506..d0dcce91a 100644
--- a/lbry/blockchain/lbrycrd.py
+++ b/lbry/blockchain/lbrycrd.py
@@ -90,7 +90,7 @@ class Lbrycrd:
             Config.with_same_dir(tempfile.mkdtemp()).set(
                 lbrycrd_rpc_port=9245 + 2,  # avoid conflict with default rpc port
                 lbrycrd_peer_port=9246 + 2,  # avoid conflict with default peer port
-                lbrycrd_zmq_blocks="tcp://127.0.0.1:29000"
+                lbrycrd_zmq_blocks="tcp://127.0.0.1:29002"  # avoid conflict with default port
             )
         ))
 
@@ -243,6 +243,8 @@ class Lbrycrd:
             self.subscription = None
 
     async def rpc(self, method, params=None):
+        if self.session.closed:
+            raise Exception("session is closed! RPC attempted during shutting down.")
         message = {
             "jsonrpc": "1.0",
             "id": "1",
diff --git a/lbry/blockchain/sync/synchronizer.py b/lbry/blockchain/sync/synchronizer.py
index 003b24efa..cea8bf751 100644
--- a/lbry/blockchain/sync/synchronizer.py
+++ b/lbry/blockchain/sync/synchronizer.py
@@ -10,10 +10,10 @@ from lbry.db.query_context import Event, Progress
 from lbry.event import BroadcastSubscription
 from lbry.service.base import Sync, BlockEvent
 from lbry.blockchain.lbrycrd import Lbrycrd
+from lbry.error import LbrycrdEventSubscriptionError
 
 from . import blocks as block_phase, claims as claim_phase, supports as support_phase
 
-
 log = logging.getLogger(__name__)
 
 BLOCKS_INIT_EVENT = Event.add("blockchain.sync.blocks.init", "steps")
@@ -43,9 +43,25 @@ class BlockchainSync(Sync):
         self.advance_loop_task: Optional[asyncio.Task] = None
         self.advance_loop_event = asyncio.Event()
 
+    async def wait_for_chain_ready(self):
+        while True:
+            try:
+                return await self.chain.ensure_subscribable()
+            except asyncio.CancelledError:
+                raise
+            except LbrycrdEventSubscriptionError as e:
+                log.warning(
+                    "Lbrycrd is misconfigured. Please double check if"
+                    " zmqpubhashblock is properly set on lbrycrd.conf"
+                )
+                raise
+            except Exception as e:
+                log.warning("Blockchain not ready, waiting for it: %s", str(e))
+                await asyncio.sleep(1)
+
     async def start(self):
         self.db.stop_event.clear()
-        await self.chain.ensure_subscribable()
+        await self.wait_for_chain_ready()
         self.advance_loop_task = asyncio.create_task(self.advance())
         await self.advance_loop_task
         await self.chain.subscribe()
diff --git a/tests/integration/blockchain/test_blockchain.py b/tests/integration/blockchain/test_blockchain.py
index e8f0de508..f99836fd5 100644
--- a/tests/integration/blockchain/test_blockchain.py
+++ b/tests/integration/blockchain/test_blockchain.py
@@ -309,19 +309,19 @@ class TestLbrycrdAPIs(AsyncioTestCase):
         await chain.stop()
 
         # lbrycrdr started with zmq, ensure_subscribable updates lbrycrd_zmq_blocks config
-        await chain.start('-zmqpubhashblock=tcp://127.0.0.1:29000')
+        await chain.start('-zmqpubhashblock=tcp://127.0.0.1:29005')
         self.assertEqual(chain.ledger.conf.lbrycrd_zmq_blocks, '')
         await chain.ensure_subscribable()
-        self.assertEqual(chain.ledger.conf.lbrycrd_zmq_blocks, 'tcp://127.0.0.1:29000')
+        self.assertEqual(chain.ledger.conf.lbrycrd_zmq_blocks, 'tcp://127.0.0.1:29005')
         await chain.stop()
 
         # lbrycrdr started with zmq, ensure_subscribable does not override lbrycrd_zmq_blocks config
         chain.ledger.conf.set(lbrycrd_zmq_blocks='')
-        await chain.start('-zmqpubhashblock=tcp://127.0.0.1:29000')
+        await chain.start('-zmqpubhashblock=tcp://127.0.0.1:29005')
         self.assertEqual(chain.ledger.conf.lbrycrd_zmq_blocks, '')
-        chain.ledger.conf.set(lbrycrd_zmq_blocks='tcp://external-ip:29000')
+        chain.ledger.conf.set(lbrycrd_zmq_blocks='tcp://external-ip:29005')
         await chain.ensure_subscribable()
-        self.assertEqual(chain.ledger.conf.lbrycrd_zmq_blocks, 'tcp://external-ip:29000')
+        self.assertEqual(chain.ledger.conf.lbrycrd_zmq_blocks, 'tcp://external-ip:29005')
 
     async def test_block_event(self):
         chain = Lbrycrd.temp_regtest()
@@ -613,6 +613,22 @@ class TestMultiBlockFileSyncing(BasicBlockchainTestCase):
 
 
 class TestGeneralBlockchainSync(SyncingBlockchainTestCase):
+    async def test_sync_waits_for_lbrycrd_to_start_but_exits_if_zmq_misconfigured(self):
+        await self.sync.stop()
+        await self.chain.stop()
+        sync_start = asyncio.create_task(self.sync.start())
+        await asyncio.sleep(0)
+        self.chain.ledger.conf.set(lbrycrd_zmq_blocks='')
+        await self.chain.start()
+        with self.assertRaises(LbrycrdEventSubscriptionError):
+            await asyncio.wait_for(sync_start, timeout=10)
+
+        await self.chain.stop()
+        await self.sync.stop()
+        sync_start = asyncio.create_task(self.sync.start())
+        await self.chain.start('-zmqpubhashblock=tcp://127.0.0.1:29005')
+        await sync_start
+        self.assertTrue(sync_start.done())
 
     async def test_sync_advances(self):
         blocks = []