In order to send email alerts from your iCloud account within MotiveWave you will need to follow the steps outlined below.
Follow the instructions on creating app-specific passwords as mentioned on the following page: https://support.apple.com/en-ca/HT204397
Enter the following settings in MotiveWave including the password you received in the first step. Substitute username@icloud.com with your iCloud email address. Do not Send Test Email until you click Apply, OK and then restart MotiveWave. After restart, try Send Test Email from within MotiveWave.