Several things affect whether your SMS reaches the recipient: number format, opt-out, sender name, content and the rules in each market. This article helps you troubleshoot SMS that don't arrive.
Watch our video on this topic (go to timestamp 17:05):
Problems in several markets
If the problem is the same across several markets, check:
- Number format: mobile numbers must start with 00 or + followed by the country code, for example 0046 or +46 for Sweden.
- Opt-out: many operators block messages that don't give the recipient a way to opt out. Always include one.
- Alphanumeric sender: check which sender types are allowed in the receiving market. Some markets don't allow alphanumeric sender names such as "Customer X" and require a number instead. Alphanumeric sender names can be at most 11 characters.
Problems in one market
If the problem is limited to one market, operators may be blocking the route into that country. Symplify monitors this, and if it happens a new route is used for the next sendout.
Some markets regulate SMS content more strictly, among others New Zealand, Thailand and North America (+1). Operators there block traffic based on the content of the SMS. If your SMS don't arrive, something in your content may trigger the operators' filters:
- Words like "bonus" or "offer" can lower deliverability into some countries. The words that are filtered change constantly.
- The sender name can be blocked by the operator. Try another sender name.
- Links and short links can lower deliverability.
- Some countries require sender authentication. Contact your account manager for guidance.
- Sender ID registration: more and more markets require alphanumeric sender IDs to be registered before SMS are delivered. The requirements are introduced market by market, so an unregistered sender ID can be blocked once a market's requirement takes effect. Contact your Customer Success Manager to find out whether the markets you send to require registration, and for help registering your sender IDs in time.
- Send during reasonable hours. Some filters only accept sendouts in the daytime.
Canada is one of the more strictly regulated markets. It only supports SMS of up to 140 characters, compared with the usual 160.
Keep up to date with the regulations in each market you send to, so your SMS are accepted by the operators.