Index Optimize jobs failed with an error SQLSTATE 01000] (Message 50000)

What could be the reason? I already checked the L: drive, so that is not the cause. Please seeking your help and thank you in advance

Message Executed as user:xxxx. … Server: xxxx [SQLSTATE 01000] (Message 50000) Version: xxx [SQLSTATE 01000] (Message 50000) Edition:xx Edition (64-bit) [SQLSTATE 01000] (Message 50000) Platform: Windows [SQLSTATE 01000] (Message 50000) Procedure: [xxxxxx.[dbo].[IndexOptimize] [SQLSTATE 01000] (Message 50000) Parameters: @Databases = ‘USER_DATABASES’, @FragmentationLow = NULL, @FragmentationMedium = ‘INDEX_REORGANIZE,INDEX_REBUILD_ONLINE,INDEX_REBUILD_OFFLINE’, @FragmentationHigh = ‘INDEX_REBUILD_ONLINE,INDEX_REBUILD_OFFLINE’, @FragmentationLevel1 = 5, @FragmentationLevel2 = 30, @MinNumberOfPages = 1000, @MaxNumberOfPages = NULL, @SortInTempdb = ‘N’, @MaxDOP = NULL, @FillFactor = NULL, @PadIndex = NULL, @LOBCompaction = ‘Y’, @UpdateStatistics = ‘ALL’, @OnlyModifiedStatistics = ‘Y’, @StatisticsModificationLevel = NULL, @StatisticsSample = NULL, @StatisticsResample = ‘N’, @PartitionLevel = ‘Y’, @MSShippedObjects = ‘N’, @Indexes = NULL, @TimeLimit = NULL, @Delay = NULL, @WaitAtLowPriorityMaxDuration = NULL, @WaitAtLowPriorityAbortAfterWait = NULL, @Resumable = ‘N’, @AvailabilityGroups = NULL, @LockTimeout = NULL, @LockMessageSeverity = 16, @StringDelimiter = ‘,’, @DatabaseOrder = NULL, @DatabasesInParallel = ‘N’, @ExecuteAsUser = NULL, @LogToTable = ‘N’, @Execute = ‘Y’ [SQLSTATE 01000] (Message 50000) Version: xxx[SQLSTATE 01000] (Message 50000) Source: https://ola.hallengren.com [SQLSTATE 01000] (Message 50000) [SQLSTATE 01000] (Message 50000) Date and time: xxxx[SQLSTATE 01000] (Message 50000) Database: [xxxxx] [SQLSTATE 01000] (Message 50000) State: ONLINE [SQLSTATE 01000] (Message 50000) Standby: No [SQLSTATE 01000] (Message 50000) Updateability: READ_WRITE [SQLSTATE 01000] (Message 50000) User access: MULTI_USER [SQLSTATE 01000] (Message 50000) Recovery model: FULL [SQLSTATE 01000] (Message 50000) Is accessible: Yes [SQLSTATE 01000] (Message 50000) [SQLSTATE 01000] (Message 50000) Date and time: xxxx [SQLSTATE 01000] (Message 50000) Database context: [xxxxx] [SQLSTATE 01000] (Message 50000) Command: UPDATE STATISTICS [AlwaysOn].[AvailabilityDatabase] [IX_AvailabilityDatabase_Group] [SQLSTATE 01000] (Message 50000) Comment: ObjectType: Table, IndexType: Index, IndexType: NonClustered, Incremental: N, RowCount: 48, ModificationCounter: 115 [SQLSTATE 01000] (Message 50000) Outcome: Succeeded [SQLSTATE 01000] (Message 50000) Duration: 00:00:00 [SQLSTATE 01000] (Message 50000) Date and time: xxxxxxx [SQLSTATE 01000] (Message 50000) [SQLSTATE 01000] (Message 50000) Date and time: xxxxx [SQLSTATE 01000] (Message 50000) Database context: [xxxxx] [SQLSTATE 01000] (Message 50000) Command: UPDATE STATISTICS [AlwaysOn].[AvailabilityDatabase] [IX_Unique] [SQLSTATE 01000] (Message 50000) Comment: ObjectType: Table, IndexType: Index, IndexType: NonClustered, Incremental: N, RowCount: 48, ModificationCounter: 39 [SQLSTATE 01000] (Message 50000) Outcome: Succeeded [SQLSTATE 01000] (Message 50000) Duration: 00:00:00 [SQLSTATE 01000] (Message 50000) Date and time: xxx [SQLSTATE 01000] (Message 50000) [SQLSTATE 01000] (Message 50000) Date and time: xxxxxx [SQLSTATE 01000] (Message 50000) Database context: [xxxx] [SQLSTATE 01000] (Message 50000) Command: UPDATE STATISTICS [AlwaysOn].[AvailabilityDatabaseReplicaState] [PK_AvailabilityDatabaseReplicaState] [SQLSTATE 01000] (Message 50000) Comment: ObjectType: Table, IndexType: Index, IndexType: Clustered, Incremental: N, RowCount: 127, ModificationCounter: 4 [SQLSTATE 01000] (Message 50000) Outcome: Succeeded [SQLSTATE 01000] (Message 50000) Duration: 00:00:00 [SQLSTATE 01000] (Message 50000) Date and time: xxxxx [SQLSTATE 01000] (Message 50000) [SQLSTATE 01000] (Message 50000) Date and time: xxxx [SQLSTATE 01000] (Message 50000) Dat… The step failed.

Error log: Message [LOG] Unable to send job completion notification email to operator ‘xxx’ for job ‘Index Opt.’

Does it mean the job succeeded but unable to send email?