Credit providers are not allowed to offer credit to everyone. They have to ensure that the person asking for credit can actually pay back what they borrow.
This is why credit providers perform what is called an affordability assessment when you apply for credit.
They ask how much you earn (and ask for proof), they ask how much you spend each month on living expenses (things like groceries and electricity) and they ask you who else you owe money to each month (your other debts).
They also draw a credit bureau report to check that you have given accurate information.
If they see that you cannot afford to make the monthly debt repayments on the amount you want to borrow, they have to say no. Otherwise, they can be accused of offering credit “recklessly”. That comes with big fines and makes shareholders very unhappy.
If you have been in debt review but still have debt left, when a credit provider does such an assessment, they will quickly see that you cannot afford the new credit yet. Once your debts are paid up they will see that you can easily afford new credit.