Your call goes straight to voicemail every time, with no ringing
Your calls go unanswered consistently, while they previously answered regularly
You can’t leave voicemails (or they immediately fail), while you normally can
Your text messages show as delivered but never as read (iMessage), despite prior behavior
Your SMS texts never show delivery confirmation (Android), or consistently fail to deliver
Your chat features (read receipts, typing indicators) stop updating (where applicable)
You can’t see their profile photo/status updates that you previously could (only if your app settings allow it)
Your call attempts show no change despite multiple times of day and days passing
Their number is still active and you can reach them through other channels, but not through your number
You see “blocked” signals specific to your carrier/app (if available in your messaging interface)