i forgot my encrypt iphone backup password

There's no way to recover your passcode to an encrypted backup of your phone.

In order to create encrypted backups in the future, you have to reset it or it will backup with previous passcode that you forgot.

To do so, head to Settings on your iPhone > General > Reset > Reset All Settings.

This won't affect your data, but will reset all of your settings like screen brightness, wallpaper, sounds and a passcode for an encrypted backup.