The term "deadbeat dad" gets thrown around a lot when people do not pay child support, but it is somewhat stereotypical. It is possible, of course, for both mothers and fathers to fail in their obligations to pay child support. The term is generally applied to men because they have historically been ordered to pay support more often than women, but that is not always the case in the modern world, where women work more often than they did in previous generations.
Another common misconception about the term is that it applies to anyone who does not pay support. In actuality, the problem arises when someone has money to pay support and just refuses to do so, in violation of the court order. That is illegal and it only harms the family.
However, some people do not have the means to pay, perhaps due to losing a job or seeing their hours and wages cut over time. Jobs are not always as stable as we hope.
In that situation, the person may be able to ask the court for a modification. The support may get reduced so that it becomes affordable again. This is far different from simply choosing not to pay.
Of course, it is important for people to understand their obligations and the legal process. For instance, even if you lose your job, you should never stop paying or "modify" your payments on your own. You always want to go through the court and get an official order backing up that modification. That's what you're legally obligated to pay. Even if your ex agrees to a reduction, never violate a standing order.