Ethereum layer-2 network zkSync’s Era faced a temporary block production halt today but is now back in full operation following a bug-related disruption that lasted over four hours.

In a Dec. 25 post on X, the developers confirmed that a bug within its server triggered an automated safety protocol, causing network issues.

“The zkSync Era network is now fully operational. At 05:50 UTC, one of the network’s automated safety protocols was triggered by a bug in the server. This issue required teams to inspect and is now fully resolved,” the team said.

The  Matter Labs-backed layer-2 network developers promised to share a post-mortem report soon.

However, CryptoSlate’s examination of the zkSync’s Era website via Uptime, a website monitoring platform, indicated that an outage occurred on the layer-2’s Sequencer around 6:56 am CET on Dec. 25 and services were restored by 10:56 am CET.

The Sequencer plays an important role in layer-2 networks by verifying, organizing, and compacting transactions for transfer to layer-1 chains such as Ethereum.

ChainLight, a blockchain security audit company, discovered a vulnerability in the protocol last month. The bug would allow a malicious actor to manipulate transactions within a block and still have them verified as accurate. If exploited, the vulnerability could have drained 100,000 Ethereum from the protocol.

Since its launch, zkSync’s Era has experienced substantial growth, ranking among the top 5 layer-2 networks in terms of total value of assets, according to L2beat data. Around $570 million in digital assets are locked on the protocol as of press time.

Notably, the protocol recently integrated Chainlink’s price feeds via its inclusion in the Oracle blockchain’s SCALE (Sustainable Chainlink Access for Layer-1 and 2 Enablement).