Medium<\/a> as bulk or promotional traffic, quietly discarding them before they ever hit your inbox.<\/span><\/p>\nThink about it: your carrier’s SMS gateway looks at Medium’s sender ID, checks it against a reputation database, and makes a split-second keep-or-toss decision. If Medium’s sender ID scores low on your carrier’s network that particular day? Your code vanishes. No notification. No trace.<\/span><\/p>\nThe FCC has documented how wireless carriers use automated filtering to block unwanted texts, and legitimate OTPs sometimes get caught in that crossfire.<\/span><\/p>\nFormatting matters too. If your number in Medium’s system lacks the country code or uses local format instead of the international E.164 standard, routing can fail before the message even leaves the network. Medium might accept the number visually, but the carrier’s routing engine rejects it.<\/span><\/p>\nNetwork & Roaming Glitches<\/b><\/h3>\n
Wi-Fi calling seems convenient, right? Except it can completely break SMS routing. Your phone shows a perfect Wi-Fi signal, but the carrier’s SMS gateway isn’t properly tagged to the session. RFC 5724, the standard for SMS delivery over IP networks, requires specific session initiation protocol handling, and many consumer networks don’t configure it correctly.<\/span><\/p>\nThen there’s roaming. Partner networks sometimes strip SMS content or gate OTP traffic entirely as a fraud-prevention measure. Some carriers in Europe and Asia automatically block SMS from unknown international senders when you’re roaming, even when you’ve paid for roaming data. Frustrating? Absolutely.<\/span><\/p>\n
![\"Medium](\"https:\/\/pvapins.com\/blog\/wp-content\/uploads\/2026\/08\/ChatGPT-Image-Aug-27-2026-11_07_55-PM.png\")
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