SQL Job Fails Logging In to Integration Services
In SQL Server 2012, you should typically use the SSIS Catalog (database name is SSISDB) for storing your packages for execution. You can still store them in MSDB, but this is not recommended.

Double-check your SQL Agent job that it is not trying to connect to the SSIS catalog to execute the package, in which case it will fail because A) you probably don't have access to SSISDB (it may not even be configured), and B) the package is not in SSISDB, but MSDB.

Check the agent job and confirm that the package source is set to SQL Server and not SSIS Catalog to verify you're trying to run from the correct location.

Also, if you can post the full details of the error message it will help to identify your root issue quicker.

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