Hi @Alice01 ,
Welcome to Microsoft Q&A!
Have you ever changed the server name or NT Account before? For example, you changed the hostname of a Windows server with SQL Server already installed. Internally SQL Server still shows the old hostname this must be dropped manually. Otherwise your SQL Server maintenance plan jobs fail with this error. Please refer to Fixing Maintenance Plan Error code 0x534 to get more details.
Best regards,
Carrin
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