This is my regex (for international phone number), i have the message "Syntax Error" with this part of regex highlighted :
s*[)]?[-\s.]?[(]?[0-9]{1,3}[)]?([-\s.]?[0-9]{3})([-\s.]?[0-9]{3,4})')
This is the regex and the regex tester online : https://www.regextester.com/97440
AND(
$Setup.ActivationSettings__c.VR_Contact__c,
OR(
AND(
!ISBLANK( Phone ),
!REGEX( Phone , '(([+][(]?[0-9]{1,3}[)]?)|([(]?[0-9]{4}[)]?))\s*[)]?[-\s\.]?[(]?[0-9]{1,3}[)]?([-\s\.]?[0-9]{3})([-\s\.]?[0-9]{3,4})')
),
AND(
!ISBLANK( MobilePhone ),
!REGEX( MobilePhone , '(([+][(]?[0-9]{1,3}[)]?)|([(]?[0-9]{4}[)]?))\s*[)]?[-\s\.]?[(]?[0-9]{1,3}[)]?([-\s\.]?[0-9]{3})([-\s\.]?[0-9]{3,4})')
)
)
)
Thanks