Hello,
Thank you for posting question on Microsoft Windows Forum!
To address your query without specific error message being provided. Well! If this is a work or school account, your system administrator is indeed the best person to fix it because they manage the "keys" to the organization's server.
However, if this is a personal account. You should make sure that you are entering the right email and password. Also confirm to connect to a stable network. You can try to clear your browser cache/cookies or try a different browser.
The suggested methods for account recovery is to use Two-step verification. If you have security info (like a phone number or alternate email), use it to verify your identity. Other one is to use the Microsoft account recovery form to submit details about your account (previous passwords, recent email subjects, contacts you’ve emailed, device info). Please consult this article for more information regarding Recovery Form https://support.microsoft.com/en-us/account-billing/help-with-the-microsoft-account-recovery-form-b19c02d1-a782-dee6-93c3-dc8113b20c42
Hope the above information is helpful! If it is. Free feel to hit "Accepted" for benefitting others in community having the same issue too.