The project team reports that the issue has now been resolved. We explain what happened to Sui and how developers fixed the bugs.
The Sui Foundation team has published a detailed report on the causes of three mainnet outages that occurred on May 28 and 29, 2026. Total downtime exceeded 15 hours.
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Contents
Causes of the Sui Incidents
All three halts were linked to the upgrade to version 1.72, which introduced a new Address Balances feature and gasless stablecoin transfers.
- First halt (May 28, approximately 6.5 hours)
A bug in the gas fee mechanism. Transactions were rejected due to insufficient funds, but the network still deducted gas, creating negative balances. This caused a failure during validators’ balance reconciliation.
- Second halt (May 29, morning)
Caused by an interim patch for the first error. The team knew there was a “low probability” of another failure but deliberately took the risk to restore the network faster.
- Third halt (May 29, evening, about 43 minutes)
A completely different issue. When restarting nodes after installing the final fix, a hidden bug related to random number generation settings persisting between epochs was triggered. Validators could not finalize data and close the epoch.
Consequences for Sui and Measures Taken
The Sui Foundation emphasized that user funds were completely safe and that confirmed transactions were not rolled back. All identified bugs have been fixed, and the network is operating normally.
To accelerate diagnostics and analysis of validator logs, the team successfully used AI agents.
Read more: Top 10 Cryptocurrencies with the Lowest Transaction Fees in 2026
Market Reaction to Sui’s Problems
The SUI▼$0.7005 token dropped significantly following the incidents. Over the past week, it has lost about 16%. At the time of publication, SUI trades at approximately $0.87, down nearly 3% over 24 hours.
As of June 1, the SUI token price is approximately 83% below its all-time high of $5.35.
Sui has faced serious outages before. In January 2026, the network was unavailable for more than 6 hours, and in November 2024, for about 2.5 hours.
Despite reliability issues, Sui remains one of the fastest Layer-1 blockchains and continues to develop its ecosystem. However, recurring outages after major upgrades raise questions among investors about the network’s stability.
Learn more: Top 5 Sui Tokens to Watch in 2026 — Best Picks for Early Investors
