I am running the job getting below error while on changing job owner to first account job is working

I have two sa accounts on sql server 2008 R2:

1. xyz-NDC-SDB2-U\Administrator
2. xyz-NDC-SDB2-U\UATDBADMIN

From second account a new job is created and sql server service is running from first account.

When I am running the job getting below error while on changing job owner to first account job is working:

Error code 0x5. [SQLSTATE 42000] (Error 15404): Could not obtain information about Windows NT group/user MyDomain\MyUserName'

I want to run my job using second account.

Thanks