When it does not work
The browser never came back
dlab auth login waits for a browser to hand it your sign-in. If the tab opened but nothing happened in the terminal, the command had already stopped waiting — run it again and complete the sign-in promptly.
“requires a licence” after signing in
Signing in creates an account; it does not grant access. Access comes from an activation link. Open your account to see which of the two you have.
Where the licence is kept
~/.config/dlab/licence, or the path named in the error. Deleting it is safe: run dlab auth login again. DLAB_LICENSE and DLAB_LICENSE_FILE take precedence over it, which is worth checking if the file looks right and dlab disagrees.
Signing out
dlab auth logout removes the licence from this machine. Signing out in the browser does not.
Still stuck
Send us the output of dlab auth status and dlab --version. Neither contains your licence.