Once a number is unblocked, the change is immediate. No device restart is required. However, the restoration of communication follows specific rules:
Users may confuse a blocked number with the "Silence Unknown Callers" feature. If a number is unblocked but still does not ring, the user should navigate to . If this toggle is enabled, calls from numbers not in the user's Contacts will be silenced and sent to voicemail, mimicking the behavior of a blocked number. unblock phone numbers iphone