EP/S pass application rejected

[mac]

The company which is applying for my EP/s pass just called me today and told me that my application has been rejected! They are currently appealing for me, can anyone tell me what are the odds of getting my s pass after being rejected once?

What are the more common reasons for s pass application being turned down? I have a bachelor degree in Engineering, though the basic salary the company offers me is less than 2.5K per month, it is close. I was a pr once, i renounced my pr status when i was 18 and left the country to study aboard without serving NS. Could that be the problem?? I've spoken with the immigration personnel when i extended my social visit pass and he told me that i might have a problem if i apply for pr again, as for employment pass, shouldn't be a problem. Can anyone with some understandings of singapore immigration laws please advise me on what to do. Thank u!!!!