, especially when traffic is high or the route looks suspicious.<\/span><\/p>\nThe usual culprits:<\/span><\/p>\n\n- Automated <\/span>carrier spam detection<\/b><\/li>\n
- Short-code vs long-code routing quirks<\/span><\/li>\n
- Peak-hour congestion (yep, OTPs can \u201ctraffic jam\u201d)<\/span><\/li>\n
- International routing delays and extra hops<\/span><\/li>\n<\/ul>\n
Delivery success varies by carrier and region, which is why two people can do the <\/span>same thing<\/span><\/i> and get totally different results.<\/span><\/p>\n![\"Illustration](\"https:\/\/pvapins.com\/blog\/wp-content\/uploads\/2026\/01\/Illustration-of-an-OTP-text-message-being-filtered-by-a-carrier-spam-shield-causing-Twitch-verification-delays.webp\")
<\/p>\n
United States carriers (Verizon, AT&T, T-Mobile)<\/b><\/h3>\n
In the US, filtering can be aggressive. If you request too many codes quickly, or the message route is considered risky, you\u2019ll see delays or blocks.<\/span><\/p>\nWhat tends to work best:<\/span><\/p>\n\n- Wait out the cooldown instead of hammering \u201cResend.\u201d<\/span><\/li>\n
- Avoid switching networks mid-attempt<\/span><\/li>\n
- If you\u2019re stuck, change the delivery route (more on that below)<\/span><\/li>\n<\/ul>\n
International delivery delays (global users)<\/b><\/h3>\n
Outside the US, OTP SMS often passes through multiple carrier hops. More hops = more delay = more timeouts.<\/span><\/p>\nTwo things matter a lot here:<\/span><\/p>\n\n- Choosing the correct country code<\/span><\/li>\n
- Using a cleaner delivery route that\u2019s less likely to be filtered<\/span><\/li>\n<\/ul>\n
For background on why filtering and delays happen at the carrier level, see the <\/span>GSMA guidance on messaging ecosystems and filtering<\/b>.<\/span><\/p>\n <\/p>\n
![\"Person](\"https:\/\/pvapins.com\/blog\/wp-content\/uploads\/2026\/01\/Person-holding-a-phone-on-the-Twitch-login-screen-with-OTP-not-received-and-an-empty-SMS-inbox.webp\")
<\/p>\n