What might prevent an end user from being authenticated when using MFA?

Too many unsuccessful attempts can indeed prevent an end user from being authenticated when using multi-factor authentication (MFA). MFA systems often implement security measures to protect against brute-force attacks, which can consist of an attacker repeatedly trying to guess authentication codes. When a user exceeds a predefined limit for failed attempts, the system typically locks the account temporarily or requires additional verification steps before allowing further attempts. This precaution helps to safeguard user accounts by ensuring that only legitimate users can access them after a certain threshold of failed attempts is reached.

In contrast, network connectivity issues might prevent the MFA system from functioning properly, but they do not inherently lock or block a user account. Expired user credentials could indeed stop authentication but would typically be addressed by an error prompt or a user-directed account recovery process. A disabled user account would also prevent access but is part of a broader user management issue rather than specifically related to MFA attempts. All these scenarios reflect different operational aspects, but exceeding the limit on unsuccessful authentication attempts directly indicates a security mechanism that actively locks out the user for safety reasons.