Alert types
Manual runs do not send a failure email. Their errors show on the canvas while you work. Failure alerts cover only workflows that run without you watching.
Managing your alerts

Settings → Notifications, with a toggle for each alert type.
1
Open notification settings
Go to Settings → Notifications. Each alert type has its own toggle.
2
Turn types on or off
Switch any type off to stop receiving those emails. Changes save as you toggle them.