Windows Live Custom Domains causes Entra account lockout

Hi Daniel, this is most likely caused by old cached credentials or legacy services still trying to sign in with Microsoft systems. Windows Live Custom Domains has been retired and replaced by Microsoft 365 and Entra ID, but some applications or devices may still attempt to connect using those old endpoints. To investigate further, check the Entra ID sign-in logs, which will show the IP addresses or apps that are generating the failed attempts. Once you know the source, you can see if it is an older client or a background process using saved credentials. If the issue continues, resetting the affected users’ passwords and making sure they sign in again on their devices usually resolves it. The good news is this is rarely a compromise and more often a leftover service repeatedly trying to use outdated details.