Validation rule on Email and (phone or Mobile)

Question

Validation rule on Email and (phone or Mobile) must be field with values. I have also tried ISBLANK( MobilePhone ) || ISBLANK( Phone ) but I get validation on both fields and and if one of them has a value then lead can be converted

AND(
    IsConverted,
    OR(
        ISBLANK( Email ),
        ISNUMBER( MobilePhone ) || ISNUMBER( Phone ) 
    )
)

What am I missing?

Answer 1

You need to change your validation rule like this:-

AND(
    IsConverted,
    OR(
        ISBLANK( Email ),
        AND(
            (
                NOT(ISNUMBER( MobilePhone )) ||
                ISBLANK(MobilePhone)
            ),
            (
                NOT(ISNUMBER( Phone )) ||
                ISBLANK(MobilePhone)
            )
        ) 
    )
)

so basically, you have to return true only when both mobilenumber and phone are not number or they are blank.