Will God Not Answer My Prayers if I’m Doubting He will?

Questions about why Hebrews is included in the New Testament canon if the author is unknown and whether God won’t answer your prayers if you’re doubting he will.

• If apostolic authority was an important factor in deciding which books to include in the New Testament canon as Scripture, then why was Hebrews included if the author is unknown?
• I’m beginning to doubt the efficacy of prayer since so many of my prayers don’t seem to be answered. Will God now not answer my prayers if I’m doubting he will?