我们在重新启动sonarqube 6.7.2时遇到以下错误，有人可以提供建议。谢谢。
2018.04.04 10:31:44 ERROR web[][DbMigrations] #1619 'Restore 'sonar-users' group': failure | time=8ms
2018.04.04 10:31:44 ERROR web[][DbMigrations] Executed DB migrations: failure | time=9ms
2018.04.04 10:31:44 ERROR web[][o.s.s.p.d.m.DatabaseMigrationImpl] DB migration failed | time=56ms
2018.04.04 10:31:44 ERROR web[][o.s.s.p.d.m.DatabaseMigrationImpl] DB migration ended with an exception
org.sonar.server.platform.db.migration.step.MigrationStepExecutionException: Execution of migration step #1619 'Restore 'sonar-users' group' failed
at org.sonar.server.platform.db.migration.step.MigrationStepsExecutorImpl.execute(MigrationStepsExecutorImpl.java:79)
at org.sonar.server.platform.db.migration.step.MigrationStepsExecutorImpl.execute(MigrationStepsExecutorImpl.java:67)