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SQL Server error code

SQL Server error 988

SQL Server raises error 988 at severity 14, which marks a problem with the query or data that you can correct.

Unable to access database '%.*ls' because it lacks a quorum of nodes for high availability. Try the operation again later.
Msg988
NameDB_HADRON_DATABASE_NO_QUORUM
Severity14
Group0–999

What it means

The REQUIRED_SYNCHRONIZED_SECONDARIES_TO_COMMIT setting enforces that the primary replica must wait for a specified number of synchronous secondary replicas to harden each transaction before committing. If the required number of replicas isn't online, connected, and synchronized, you might encounter the following issues, which lead to blocking or failure scenarios that trigger error 988.

The primary replica can't complete commits. - A database being added can't complete the join process, as secondaries aren't yet participating.

Source: Database Engine events and errors