The Arbitrum Sepolia testnet experienced a partial outage, halting block production for several hours due to a suspected issue in its core Nitro infrastructure. Developers identified a potential block divergence and paused block production while working on a fix. The team is preparing a new Nitro release to restore operations, advising developers to pause time-sensitive testing. No user funds are at risk as the mainnet remains unaffected.
Arbitrum‘s Sepolia testnet has experienced a partial outage, with block production halted for hours. The issue is suspected to be in the network’s core Nitro infrastructure.
In an update shared by the Arbitrum developers, the team said block production was temporarily paused after identifying a potential block divergence. The team is currently working on an infrastructure update to restore normal operations.
Data from the Arbitrum Sepolia explorer shows no new transactions have been processed for roughly 3–4 hours. This confirms the network is fully stalled.
The latest recorded batches and transactions are timestamped several hours ago. The explorer shows it is still scanning for new transactions with no activity.
According to the team, the root cause appears related to Nitro, Arbitrum’s core scaling system. Block divergence occurs when nodes disagree on the chain state, preventing consensus.
The team said no action is required from infrastructure providers at this stage. Node operators will need to upgrade once a patched Nitro version is released.
The outage primarily affects developers using Sepolia for contract deployment. Arbitrum has advised developers to pause time-sensitive testing and consider alternative environments.
Infrastructure providers have also been warned to expect a stalled chain head. Normal operations will resume only after block production restarts.
The team emphasized that no user funds are at risk. The issue is limited to the Sepolia testnet environment.
Arbitrum said it is actively investigating and will release a new Nitro version. Further updates are expected as the team progresses toward restoration.
