How to check the reasons for rejecting employment visa

Dear Madam,

I would need your help in solving my issue.

Please note I have stayed in the UAE for the past 4 years in both RAK and Dubai.

I have no criminal offence during my stay and I was employed with all reputed companies. However, last December 2018 my contract was suddenly terminated by my previous employer without any notice.

So I lost my job and had to fly back to my country. Once back, I started to look for jobs again as I needed to afford my old parents. Meanwhile, my previous employer has cancelled my work visa and I was given visa cancellation as well.

Somehow I managed to get a new job again in the UAE, however, suddenly the employer came back to me and said they are unable to apply for my new work visa because as per Immigration my profile has been blacklisted.

I have no clue why and how can that be even possible because I had a very clean track record during my stay and always abide by rules and regulations.