EP status invalid

Hi everyone, my employer applied for an EPASS for me on the 30th of May (status pending). After around 3 weeks the status changed to "invalid" with an error:

Your application has not been approved. Please talk to your employer or agent. As this is a non login portal, we are only able to offer limited information due to privacy/security issues.

After contacting my employer, I got to know that the response from MoM was

The candidate is not eligible for a work pass.

without any additional clarifications, my employer asked for clarifications but it was not given (That's what I was informed). I double-checked all the requirements and ensured that I pass the compass points system and the minimum salary requirement (base salary + additional sum > 5k SGD) and had no criminal record not even a speeding ticket.

My question is as follows:

what might be the reasons for that rejection? so I can know whether I should push my employer into appealing what modifications should be made to the application, and whether should I consider applying to another employer in Singapore or change the country completely.

I'm kinda lost and not sure whom to seek for guidance, thanks in advance.