Upgrade failed. Please consult the system logs for details. You will need to fix these problems, restore your database and confluence home directory to the pre upgrade state. Then retry the upgrade. Upgrade error message: Upgrade task com.atlassian.confluence.upgrade.upgradetask.DropSpaceGroupTablesUpgradeTask@15058912 failed during the SCHEMA_UPGRADE phase due to: null
i am running Oracle, why am I getting the following error?