Currently If a client is entered twice, the “Cell number” is the field that triggers the system to know that the client already has a record; however, this error message is not clear to the users, If a client has already been entered is it possible have the error message to appear this ie Client has already been added to the system
You can change the validation error to whatever you like but right now there’s no way to show a different error for invalid as opposed to duplicate phone number. The best option right now is to have an error message which covers both options, as shown in the issue comments.