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?