The primary reason why an active auto-invest might have failed, is because there isn't enough available cash in the Kernel wallet to process the auto-invest transaction.
Outside of simply not depositing the total auto-invest amount to cover the transaction, there are two other reasons why it might fail:
Not enough time is allowed for deposits to process, or;
The member fee has not been accounted for in the total deposited amount.
Timing your deposit correctly
It takes 1-2 business days for all deposits from nominated bank accounts to show in the Kernel wallet. Therefore, it’s important to allow a little bit of time between when you deposit, and the date of which your Auto-Invest transaction is set to process.