If adding Cash to Cash App failed, there is a strong possibility that you have a lack of funds in your bank account. In that case, you must add a balance to your bank account. However, other factors are also there like poor internet connectivity, older Cash App and server issues that may play a role in Cash App Add Cash failed.
To prevent transfer failed on Cash App, the users should use the Cash App as per the terms of services. Always use an updated Cash App, make sure proper internet speed and sufficient funds are in the bank account.