Here what does the disclosure of reason is crucial mean? You need to recognize the cause that prevented you from transferring money to your friend. The foremost aspect is that you have to stay very careful for your cash app account as sometimes insufficient amount also leads to such kind of unpredicted problems. But you can resolve it yourself by loading the required amount and make your account eligible for accepting the transfer process. Most often, interrupting in the usual activities is notified as the Cash app won't let me send money . Overall, you need to take the solution steps with your calm mind.