Docomo suspends some official sender marks after phishing reports

What Docomo announced

In a notice dated 15 October 2026, NTT Docomo says phishing messages have displayed its official account mark for some participating companies. It cites sender email authentication settings and related factors, and says it will temporarily suspend the mark for affected companies until the issue is resolved.

The notice does not identify those companies, explain the technical mechanism or give a restoration date. It introduces no new authentication requirement for all sending domains.

What administrators should check

Teams sending through Docomo's official account programme should investigate unexpected mark changes with Docomo and their mail provider. Review actual message headers, authentication results and the services authorised to send as the domain. Keep existing protections in place while investigating.

These are recommended operational checks. Docomo's notice does not prescribe a single DNS change or establish that one particular authentication protocol caused the problem.

What recipients should know

Rakuten Card's security page also warns about spoofed messages displaying its brand symbol or official account mark. It advises customers to use its official app or a saved bookmark before logging in, even when a symbol is present.