Coinbase-Backed Base Resumes Block Production After Two-Hour Mainnet Outage Halts Transactions

Coinbase-backed Ethereum layer-2 network Base resumed block production Thursday after a disruption of roughly two hours that halted the blockchain and temporarily stopped transaction processing.

“Coinbase's Base blockchain resumes after two-hour outage disrupted network The incident temporarily halted transaction processing on one of Ethereum's largest layer-2 networks”

@coindesk

The first public indication of problems came at 16:03 UTC, when Base reported that mainnet block production was "unhealthy."

@coindesk

By 16:52 UTC, the team said it had identified a problem and was pursuing multiple remediation efforts, while continuing to investigate the root cause of the incident.

The Cryptonomist said the Base mainnet outage froze block production entirely on June 25, cutting off deposits, withdrawals, and client software operations at once, after an invalid block was sequenced and the chain could not produce new blocks beyond block 47806542.

CoinDesk reported that Base advised ecosystem node operators to restart their Base nodes to restore synchronization, while saying internal nodes were syncing correctly after the outage.

The Cryptonomist described the mechanism as a consensus issue that caused an invalid block to be sequenced on Base, halting all new block production after block 47806542.

Crypto Briefing

CoinDesk also said Base has not yet disclosed what caused the invalid block or whether the issue stemmed from a software bug or another consensus-related fault, and it would continue to monitor network stability and provide further updates.

Crypto Briefing framed the broader context by saying the centralized sequencer powering Coinbase's Layer-2 network has become a recurring point of failure during high-traffic periods, and that when the sequencer goes down, the entire network effectively freezes.

CoinDesk said the incident temporarily halted transaction processing on one of Ethereum's largest layer-2 networks and that Base previously suffered an outage in August 2025, with the team continuing to investigate the root cause.

“Coinbase’s Base sequencer struggles with instability, raising scalability concerns The centralized sequencer powering Coinbase's Layer-2 network has become a recurring point of failure during high-traffic periods Base, the Ethereum Layer-2 network built by Coinbase, is facing renewed scrutiny over the stability of its sequencer, the single piece of infrastructure responsible for ordering transactions and producing blocks”

Crypto Briefing

The Cryptonomist added that the internal sequencer and nodes have partially recovered, but full block propagation had not yet been restored at the time of reporting, while the root cause of the consensus issue remained under active investigation by the Base team.

Crypto Briefing said Base runs on a centralized sequencer operated solely by Coinbase, and that if the single sequencer fails, there’s no failover mechanism that kicks in automatically to keep the network running.

It also reported that Base launched its Appchains initiative in early 2025, with the Appchains rollout beginning in February 2025, and that Base was transitioning to a unified Reth-based codebase, while noting that concrete timelines and mechanisms for sequencer decentralization remained unclear.