• Spanish operators must now block SMS, MMS and RCS messages that use unregistered sender aliases or arrive through providers not authorised for that alias
  • Eligible applications submitted before the 14 September cut-off can receive temporary pre-registration while the CNMC completes the registration process

The fact

Spain's rules requiring telecoms operators to block messages using unregistered sender aliases took effect on 15 September. The measure covers the names used by companies and public bodies in place of a telephone number when sending SMS, MMS or RCS messages.

The register is managed by Spain's National Commission on Markets and Competition, or CNMC. Each alias must be linked to the organisation entitled to use it and to the messaging providers authorised to send messages under that name. Operators must also block messages using a registered alias if they arrive from a provider that is not authorised for it.

A temporary measure covers qualifying registration requests submitted before 15:00 mainland Spanish time on 14 September. Those aliases can remain in use while outstanding checks are completed, subject to the conditions set by the CNMC. The regulator had recorded 13,565 aliases by the morning of 10 September.

The assessment

Spain's rules make branded SMS delivery depend on two things being correct: the registered sender name and the provider allowed to use it. A company may have registered its alias properly and still have messages blocked if traffic is moved to a supplier that has not been authorised for that name.

That makes supplier changes and failover planning more delicate. A new provider cannot simply take over the same sender name when traffic is switched. It needs to be authorised beforehand and tested. The same applies to backup routes. If that work has not been done, the fallback may fail at the moment it is needed.

For BTW readers, this is a continuity issue hidden inside a compliance rule. Businesses that rely on SMS for login codes, payment alerts or delivery updates need to include provider authorisation in migration and incident plans, and monitor rejection codes closely enough to tell a registration problem from an ordinary messaging failure.

What to watch

Watch delivery results through both primary and backup messaging providers after the blocking rules take effect. Businesses should track rejections linked specifically to alias registration or provider authorisation. Supplier migrations will provide an early test of whether organisations update the register before changing routes rather than discovering missing permissions after messages stop arriving.