Perhaps this question was posed under the misbelief that JWs believe this. They do not.
JWs, like all Christians, recognize that the only absolute requirement for prayer is faith, which implies humility and persistence (see (Luke 11:5-13; 18:1-14).
JWs believe that a prayerful person of faith will eventually, somehow, receive Bible knowledge through the action of holy spirit and angelic direction, including knowledge about Christ and about Christian principles. At that point, the Bible teaches that certain human actions and willful inactions can block prayer.
(Proverbs 15:29) Jehovah is far away from the wicked ones, but the prayer of the righteous ones he hears.
(Proverbs 28:9) He that is turning his ear away from hearing the law—even his prayer is something detestable.
(Isaiah 1:15) Even though you make many prayers, I [God] am not listening
(Micah 3:4) At that time they will call to Jehovah for aid, but he will not answer them. And he will conceal his face from them
For example, the Bible says the following about a husband who doesn't respect his wife...
(1 Peter 3:7) You husbands, continue dwelling in like manner with [your wives] according to knowledge...in order for your prayers not to be hindered.