# Connection between core node and relay node fail **URL:** \ **Category:** Setup a Stake Pool\ **Created:** [7 July 2021 10:55 UTC](https://forum.cardano.org/t/connection-between-core-node-and-relay-node-fail/66487 "2021-07-07T10:55:49Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![NguyenCongVn](https://avatars.discourse-cdn.com/v4/letter/n/41988e/32.png) [@NguyenCongVn](https://forum.cardano.org/u/NguyenCongVn)\ **Post date:** [7 July 2021 10:55 UTC](https://forum.cardano.org/t/connection-between-core-node-and-relay-node-fail/66487/1 "2021-07-07T10:55:49Z")
Hi everyone! I have learnt how to setup stake pool in this course `https://cardano-foundation.gitbook.io/stake-pool-course/stake-pool-guide/stake-pool/corenode-start` I using Amazon EC2 to host there nodes. But when i run core node, it’s fail for relay node to connect to core node. In relay node, it says : > [ip-172-3:cardano.node.IpSubscription:Info:165] [2021-07-07 10:51:30.10 UTC] IPs: 0.0.0.0:0 [52.0.169.106:3001] Trying to connect to 52.0.169.106:3001 > [ip-172-3:cardano.node.IpSubscription:Notice:165] [2021-07-07 10:51:30.10 UTC] IPs: 0.0.0.0:0 [52.0.169.106:3001] Waiting 0.025s before attempting a new connection > [ip-172-3:cardano.node.IpSubscription:Info:14287] [2021-07-07 10:51:30.10 UTC] IPs: 0.0.0.0:0 [52.0.169.106:3001] Connection Attempt Start, destination 52.0.169.106:3001 > [ip-172-3:cardano.node.IpSubscription:Notice:14287] [2021-07-07 10:51:30.10 UTC] IPs: 0.0.0.0:0 [52.0.169.106:3001] Connection Attempt End, destination 52.0.169.106:3001 outcome: ConnectSuccessLast > [ip-172-3:cardano.node.IpSubscription:Info:14287] [2021-07-07 10:51:30.14 UTC] IPs: 0.0.0.0:0 [52.0.169.106:3001] Closed socket to 52.0.169.106:3001 > [ip-172-3:cardano.node.IpSubscription:Info:165] [2021-07-07 10:51:31.14 UTC] IPs: 0.0.0.0:0 [52.0.169.106:3001] Restarting Subscription after 1.045980199s desired valency 1 current valency 0 I think it needs to sync blockchain but nothing new. In core node , it’s failed too > [ip-172-3:cardano.node.LeadershipCheck:Info:793] [2021-07-07 10:47:09.01 UTC] {“credentials”:“Cardano”,“kind”:“TraceStartLeadershipCheck”,“delegMapSize”:1464,“slot”:31285613,“chainDensity”:3.4998138e-2,“utxoSize”:78469} > [ip-172-3:cardano.node.ForgeTime:Info:793] [2021-07-07 10:47:09.01 UTC] fromList > [ip-172-3:cardano.node.ForgeTime:Info:793] [2021-07-07 10:47:09.01 UTC] fromList > [ip-172-3:cardano.node.ForgeTime:Info:793] [2021-07-07 10:47:09.01 UTC] fromList > [ip-172-3:cardano.node.Forge:Error:793] [2021-07-07 10:47:09.01 UTC] fromList [(“credentials”,String “Cardano”),(“val”,Object (fromList [(“kind”,String “TraceNoLedgerView”),(“slot”,Number 3.1285613e7)]))] > [ip-172-3:cardano.node.ForgeTime:Info:793] [2021-07-07 10:47:09.01 UTC] fromList This is the topology.json file in relay node: > { “Producers”: [{ “addr” : “52.0.169.106”, “port” : 3001, “valency” : 1 }, { “addr”: “[relays-new.cardano-testnet.iohkdev.io](http://relays-new.cardano-testnet.iohkdev.io)”, “port”: 3000, “continent”: “Europe”, “state”: “GB”, “valency” : 1 } ] } And the topology.json file in core node: > { > “Producers”: [ > { > “addr”: “3.225.159.56”, > “port”: 3001, > “valency”: 1 > } > ] > } When I check connection between two node by telnet. It’s successed. Please help me solve this problem! ---
**Author:** ![Xpriens](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.cardano.org/xpriens/32/45030_2.png) [@Xpriens](https://forum.cardano.org/u/Xpriens)\ **Post date:** [7 July 2021 12:02 UTC](https://forum.cardano.org/t/connection-between-core-node-and-relay-node-fail/66487/2 "2021-07-07T12:02:21Z")
Topology looks fine, let them sync first and check again. ---
**Author:** ![NguyenCongVn](https://avatars.discourse-cdn.com/v4/letter/n/41988e/32.png) [@NguyenCongVn](https://forum.cardano.org/u/NguyenCongVn)\ **Post date:** [7 July 2021 12:38 UTC](https://forum.cardano.org/t/connection-between-core-node-and-relay-node-fail/66487/3 "2021-07-07T12:38:37Z")
I run the nodes again but it still failed This message is from relay node : > [ip-172-3:cardano.node.IpSubscription:Error:496] [2021-07-07 12:37:22.28 UTC] IPs: 0.0.0.0:0 [52.0.169.106:3001] Application Exception: 52.0.169.106:3001 ExceededTimeLimit (ChainSync (Header (HardForkBlock (‘: \* ByronBlock (’: \* (ShelleyBlock (ShelleyEra StandardCrypto)) (‘: \* (ShelleyBlock (ShelleyMAEra ‘Allegra StandardCrypto)) (’: \* (ShelleyBlock (ShelleyMAEra ‘Mary StandardCrypto)) (’ \*))))))) (Tip HardForkBlock (’: \* ByronBlock (‘: \* (ShelleyBlock (ShelleyEra StandardCrypto)) (’: \* (ShelleyBlock (ShelleyMAEra ‘Allegra StandardCrypto)) (’: \* (ShelleyBlock (ShelleyMAEra ‘Mary StandardCrypto)) (’ \*))))))) (ServerAgency TokNext TokMustReply) > [ip-172-3:cardano.node.ErrorPolicy:Notice:174] [2021-07-07 12:37:22.28 UTC] IP 52.0.169.106:3001 ErrorPolicySuspendConsumer (Just (ApplicationExceptionTrace ExceededTimeLimit (ChainSync (Header (HardForkBlock (‘: \* ByronBlock (’: \* (ShelleyBlock (ShelleyEra StandardCrypto)) (‘: \* (ShelleyBlock (ShelleyMAEra ‘Allegra StandardCrypto)) (’: \* (ShelleyBlock (ShelleyMAEra ‘Mary StandardCrypto)) (’ \*))))))) (Tip HardForkBlock (’: \* ByronBlock (‘: \* (ShelleyBlock (ShelleyEra StandardCrypto)) (’: \* (ShelleyBlock (ShelleyMAEra ‘Allegra StandardCrypto)) (’: \* (ShelleyBlock (ShelleyMAEra ‘Mary StandardCrypto)) (’ \*))))))) (ServerAgency TokNext TokMustReply))) 20s .This message is from core node : > [ip-172-3:cardano.node.LeadershipCheck:Info:157] [2021-07-07 12:32:50.00 UTC] {“credentials”:“Cardano”,“kind”:“TraceStartLeadershipCheck”,“delegMapSize”:1997,“slot”:31291954,“chainDensity”:2.9968629e-2,“utxoSize”:214072} > [ip-172-3:cardano.node.ForgeTime:Info:157] [2021-07-07 12:32:50.00 UTC] fromList > [ip-172-3:cardano.node.ForgeTime:Info:157] [2021-07-07 12:32:50.00 UTC] fromList > [ip-172-3:cardano.node.ForgeTime:Info:157] [2021-07-07 12:32:50.00 UTC] fromList > [ip-172-3:cardano.node.ForgeTime:Info:157] [2021-07-07 12:32:50.00 UTC] fromList ---
**Author:** ![NguyenCongVn](https://avatars.discourse-cdn.com/v4/letter/n/41988e/32.png) [@NguyenCongVn](https://forum.cardano.org/u/NguyenCongVn)\ **Post date:** [7 July 2021 12:55 UTC](https://forum.cardano.org/t/connection-between-core-node-and-relay-node-fail/66487/4 "2021-07-07T12:55:06Z")
I run with this command : relay node : ```auto cardano-node run \ --topology testnet-topology.json \ --database-path db \ --socket-path db/node.socket \ --host-addr 0.0.0.0 \ --port 3001 \ --config testnet-config.json\ ``` core node : > cardano-node run > –topology testnet-topology.json > –database-path ./db > –socket-path ./db/node.socket > –host-addr 0.0.0.0 > –port 3001 > –config testnet-config.json > –shelley-kes-key kes.skey > –shelley-vrf-key vrf.skey > –shelley-operational-certificate node.cert ---
**Author:** ![Xpriens](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.cardano.org/xpriens/32/45030_2.png) [@Xpriens](https://forum.cardano.org/u/Xpriens)\ **Post date:** [7 July 2021 18:43 UTC](https://forum.cardano.org/t/connection-between-core-node-and-relay-node-fail/66487/5 "2021-07-07T18:43:00Z")
Both run commands seem correct. Your topology files are correct. Are your nodes fully synced?