Looking for logging into the Mattermost Html site and are not getting the correct working link for it? In such a case, you can use the links given here by searching your desired login page in the search box. If the page is present on our website then you will get all the links related to the Mattermost Html site. After that you can login as usual with your login credentials.
https://docs.mattermost.com/help/getting-started/signing-in.html
https://www.mattermost.org/
https://forum.mattermost.org/t/auto-login-for-embedded-chat-integration/5236
https://forum.mattermost.org/t/solved-default-login-credentials/6348
https://documentation.kopano.io/kopano_mattermost_manual/first_steps.html