A fix has been implemented.

We are currently observing accessibility issues affecting some users accessing Titan Email services via specific internet specific provider. The systems remain fully operational under normal network conditions, and the issue appears to be related to internet service provider level blocks or DNS filtering.

Please refer to the following Knowledge Base article for steps to bypass the issue as a temporary solution: https://support.titan.email/hc/en-us/articles/49097382677017-How-to-access-Titan-if-your-Internet-Service-Provider-is-blocking-it