Gitlab API authentication failed. Please check your gitlab's token. HTTP status code 401.

[ka2in]

When I use the the Markdown Preview in Browser, Sublime throws the error message indicated above.

[LuluDavid]

You need to register a personal access token to Gitlab.com to be able to use the Markdown to HTML facilities.
To do so, go to Gitlab.com, connect to your account, go to your profile, click on Access Tokens panel, create a new token with at least read_api rights & copy the newly created token.
Then, in sublime, go to Preferences -> Package Settings -> Markdown Preview -> Settings & in the right editor, add:

	"gitlab_personal_token":  "<YOUR_TOKEN>"

Then everything should work fine.