Abu Dhabi employment visa rejected 3 times?

I am an Indian national and I have been working with a reputed MNC bank in India for past 8 years. I have recently been selected for a role based in Abu Dhabi for a group entity of the same MNC bank. After acceptance of the employment contract from the bank, I have shared my attested degree certificate for application of emplyment visa. My visa application has been rejected 3 times. My prospective employer has informed me that my work permit was approved by the ministry of labour but security clearance was rejected by the Abu Dhabi National Security Guard. I have never travelled to UAE before and my records in the home country are clear. Kindly provide clarification on the below points:

1. What could be the possible reason for rejection by the Abu Dhabi National Security Guard?

2. Is there anything that can be done either by me or by my employer to get my name cleared?

3. Will it help if I travel to Abu Dhabi on a tourist visa and provide any kind of clearance certificate from Indian embassy in UAE confirming that my records are clean in India?

4. What is the possibility of the visa getting approved in the 4 th attempt after I travel to Abu Dhabi on a tourist visa?

I will be grateful if you could provide me clarity on the above points and advise me on the way forward.

Thanks & Regards