Sync fails after `[Code 1] rate limited`, then `Failed to find common ancestor`

[dahu33]

Description

While syncing Teku 26.3.0 it failed with several peer-side rate-limit errors followed by common-ancestor failures.

Restarting Teku resolved the issue.

At the time of the error, Teku had 8 peers on the network, all Prysm nodes.

Logs

2026-06-10 07:41:39.010 INFO -  [37mSyncing *** Slot: 833356, Head slot: 1355, Remaining slots: 832001, Target chain: a91e98..c2ea (833280) with 8 peers, Connected peers: 8 [0m
2026-06-10 07:41:39.010 INFO -  [90mSync Info *** Range: 1351 - 1475 (5 batches), Downloading: 25 slots (1 batches), Ready: 100 slots (4 batches), Batch import: in progress [0m
2026-06-10 07:41:42.877 INFO -  [32mSyncing completed [0m
2026-06-10 07:41:44.031 INFO -  [33mSyncing started [0m
2026-06-10 07:41:44.040 ERROR - Sync process failed to complete: tech.pegasys.teku.networking.eth2.rpc.core.RpcException: [Code 1] rate limited
2026-06-10 07:41:44.054 ERROR - Sync process failed to complete: tech.pegasys.teku.networking.eth2.rpc.core.RpcException: [Code 1] rate limited
2026-06-10 07:41:44.064 ERROR - Sync process failed to complete: tech.pegasys.teku.networking.eth2.rpc.core.RpcException: [Code 1] rate limited
2026-06-10 07:41:44.076 ERROR - Sync process failed to complete: tech.pegasys.teku.networking.eth2.rpc.core.RpcException: [Code 1] rate limited
2026-06-10 07:41:44.084 ERROR - Sync process failed to complete: tech.pegasys.teku.networking.eth2.rpc.core.RpcException: [Code 1] rate limited
2026-06-10 07:41:44.089 ERROR - Sync process failed to complete: tech.pegasys.teku.networking.eth2.rpc.core.RpcException: [Code 1] rate limited
2026-06-10 07:41:44.095 ERROR - Sync process failed to complete: tech.pegasys.teku.networking.eth2.rpc.core.RpcException: [Code 1] rate limited
2026-06-10 07:41:44.102 ERROR - Sync process failed to complete: tech.pegasys.teku.networking.eth2.rpc.core.RpcException: [Code 1] rate limited
2026-06-10 07:41:44.108 ERROR - Sync process failed to complete: tech.pegasys.teku.networking.eth2.rpc.core.RpcException: [Code 1] rate limited
2026-06-10 07:41:44.119 ERROR - Sync process failed to complete: java.lang.RuntimeException: Failed to find common ancestor.
2026-06-10 07:41:44.129 ERROR - Sync process failed to complete: java.lang.RuntimeException: Failed to find common ancestor.
2026-06-10 07:41:44.140 ERROR - Sync process failed to complete: java.lang.RuntimeException: Failed to find common ancestor.
2026-06-10 07:41:44.149 ERROR - Sync process failed to complete: java.lang.RuntimeException: Failed to find common ancestor.
2026-06-10 07:41:44.159 ERROR - Sync process failed to complete: java.lang.RuntimeException: Failed to find common ancestor.
2026-06-10 07:41:44.165 ERROR - Sync process failed to complete: java.lang.RuntimeException: Failed to find common ancestor.
2026-06-10 07:41:44.172 ERROR - Sync process failed to complete: java.lang.RuntimeException: Failed to find common ancestor.
2026-06-10 07:41:44.178 ERROR - Sync process failed to complete: java.lang.RuntimeException: Failed to find common ancestor.
2026-06-10 07:41:44.186 ERROR - Sync process failed to complete: java.lang.RuntimeException: Failed to find common ancestor.
2026-06-10 07:41:44.192 ERROR - Sync process failed to complete: java.lang.RuntimeException: Failed to find common ancestor.
2026-06-10 07:41:44.198 ERROR - Sync process failed to complete: java.lang.RuntimeException: Failed to find common ancestor.
2026-06-10 07:41:44.206 ERROR - Sync process failed to complete: java.lang.RuntimeException: Failed to find common ancestor.
[...]

[rolfyone]

Hey - thanks for raising - did you have peer limiting such as p2p-peer-upper-bound?

Have you tried anything like resyncing from checkpoint sync?

There's a troubleshooting here guide also...

https://docs.teku.consensys.io/how-to/troubleshoot/network

A certain number of peers would be needed to get a rough consensus, so it sounds like as much as there may be an issue, it may improve with more peers, which is why i've initially gone down that route...

The troubleshooting guide does have some directions around inbound/outbound peers etc also, which may be helpful if firewall is blocking inbound connections etc.

We can try to replicate sync with really low peers and see whats going on there also... if you have any network related settings I'd appreciate which ones you're using (values arent important) - ig if you have upper-bound, if you have advertised-ip-address set (but not the ip).