Yes. You can customize and translate error messages inside the app when you activate each validation rule.
To edit these messages:
From the Address Ninja home screen, click on the rule you want to translate.
In the "Translate error message" section, click the arrow drop-down.
You can customize your message in the available languages.
Click Save.
You can translate and edit the following rules:
Prevent Missing House Numbers
Prevent Missing Apartment, Suite, etc., Numbers
Prevent all DHL Packstation, Paketshops & Filiale
Prevent Malformatted DHL Information
Prevent Post Office Boxes
Prevent Special Characters
Set Maximum Character Count per Field
Validate for MeinEinkauf.ch
ZIP / Postal Code Format Validation
ZIP / Postal Code Block