Ethereum’s OpenEthereum client, formerly known as the Parity client, was reported to have gone down on Thursday afternoon UTC for a number of users, including the popular Etherscan block explorer.

According to multiple user reports on GitHub, the OpenEthereum client was stuck in block 12,244,294, or only 294 blocks after Berlin’s hard junction. The error message indicates that the customer is rejecting new blocks, believing that their Merkle root state is invalid.

The issue appears to only affect OpenEthereum nodes, with the most popular Geth working just fine. Issues with the OpenEthereum client led to a power failure for Etherscan, the popular block explorer. On the website, block 12,244,294 is shown as the last block mined, although other researchers have correctly updated.

The cause of the problem remains unclear and the team is currently working on diagnosing and resolving the issue. Until that happens, Etherscan will remain useless.

Since the issue only affects OpenEthereum, the Ethereum blockchain and many service providers like Infura continue to operate as expected. Unlike previous consensus errors, there is no surrogate series with discrete transactions this time. Given the timing of Berlin’s rigid junction, it appears that some changes were made incorrectly.