Non-SysAdmins have been denied permission to run DTS Execution job steps without a proxy account. The step failed.

Non-SysAdmins have been denied permission to run DTS Execution job steps without a proxy account.  The step failed.

1. Change Job_Owner to Sa, If it's not possible then you have to try 2^nd option Create a proxy account to execute SSIS package
2.  Create a Proxy account for SSIS package and assign same while executing a job.

USE MASTER

GO

CREATE CREDENTIAL [SSISProxyCredentials]

WITH IDENTITY = N'Any Sysadmin Domain Account',

SECRET = N'Password'

GO

-----------------------------------------------------

USE msdb

GO

--Drop the proxy if it is already existing

IF EXISTS (SELECT 1 FROM msdb.dbo.sysproxies WHERE name = N'SSISProxy')

BEGIN

EXEC dbo.sp_delete_proxy

@proxy_name = N'SSISProxy'

END

GO

--Create a proxy and use the same credential as created above

EXEC msdb.dbo.sp_add_proxy

@proxy_name = N'SSISProxy',

@credential_name=N'SSISProxyCredentials',

@enabled=1

GO

--To enable or disable you can use this command

EXEC msdb.dbo.sp_update_proxy

@proxy_name = N'SSISProxy',

@enabled = 1 --@enabled = 0

GO

---------------------------------------------------------

EXEC msdb.dbo.sp_grant_proxy_to_subsystem

@proxy_name=N'SSISProxy',

@subsystem_id=11 --subsystem 11 is for SSIS as you can see in the above image

GO

--View all the proxies granted to all the subsystems

EXEC dbo.sp_enum_proxy_for_subsystem

------------------------------------------------------

USE msdb

GO

--Grant proxy account access to security principals that could be

--either login name or fixed server role or msdb role

--Please note, Members of sysadmin server role are not allowed to use any proxy

EXEC msdb.dbo.sp_grant_login_to_proxy

@proxy_name=N'SSISProxy'

,@login_name=N'Any nonsysadmin account'

GO

--View logins provided access to proxies

EXEC dbo.sp_enum_login_for_proxy

GO

------------------------------------------------------

--EXEC msdb.dbo.sp_add_jobstep @job_id=@jobId, @step_name=N'SSISPackageCall',

--@step_id=1,

--@cmdexec_success_code=0,

--@on_success_action=1,

--@on_success_step_id=0,

--@on_fail_action=2,

--@on_fail_step_id=0,

--@retry_attempts=0,

--@retry_interval=0,

--@os_run_priority=0, @subsystem=N'SSIS',

--@command=N'/FILE "C:\Package.dtsx" /CHECKPOINTING OFF /REPORTING E',

--@database_name=N'master',

--@flags=0,

--@proxy_name = N'SSISProxyDemo';

Reference:
Frequently Used Queries In SQL Server