"Login failed" means, di ka pumasa sa authentication (lols pilosopo), i believe means you're connected. So it can be an issue in your clients' network or siguro kung allowed ka lang ng 1 connection, baka may traces pa yung previous connection mo before you restarted your pc.

Pero kung yung vpn application gives the same error message regardless kung connected o hindi, e baka nga issue yan sa ISP na gamit mo.