If you've failed the Medical Commission's X-Ray test compulsary for all newly arrived workers, it means there's some anomaly in your chest or lungs such as a pneumonia patch or suspected TB.

If you fail the third time around, your work visa will be denied and you'll be repatriated to your native country by your employer.

In some cases, the commission may ask you to visit the TB clinic which is located in the Rumaillah Hospital complex, for further tests. In some instances, they may allow you to undergo medication locally, provided the TB clinic and Medical Commission is satisfied that you will not contaminate others.

I suggest you visit a private clinic and find what anomalies exist in a chest X-Ray. That would possibly help prepare better for the next test.