Alternatively referred to as a sign in, a login or logon is a set of credentials used to gain access to an area requiring proper authorization. Logins grant access to and control of computers, networks, and bulletin boards, and online accounts and other services or devices. Today, most logins consist of both a username and password and may be further protected by 2FA.
Unable to log in
If the improper username or password is entered or you have forgotten them, you cannot access your account. With online services such as you Yahoo! Mail, Gmail, and Facebook, you can use the "Forgot Password" or "Reset Password" feature to receive a password reminder or link to reset your password.
If your login information is getting rejected, attempting to log in multiple times may lock the account as a security measure to prevent someone from guessing your password. If your account is locked, you may have to wait several hours or days before it can be unlocked. Alternatively, you can often contact the administrator or company to have the account unlocked.
Is it login, log in, or log-in?
When spelled as one word, "login" and "log-in" are a noun or adjective that describes the components required to sign into an account. As two words, "log in" is a verb that describes the action of accessing an account. For example, the sentence "You need to log in with your login information to read your e-mail" uses both forms of the word.
Login or logon
"Log on" and "log-on" are the same as their "log in" and "log-in" counterparts, but are not as commonly used today.