Most of the time users face login issues because of very basic mistakes. Below we have provided troubleshooting guidelines or you can call it a checklist, to help you resolve the login-related issues.
While filling the login form, make sure you are using the most updated password and not an old password. It seems obvious but it's the most common reason for authentication failures.
Users have multiple email addresses and use them on different websites, make sure you are using the correct email and password combination to sign in. An incorrect combination would not work.
Make sure your keyboard's CAPS Lock is OFF. Because the passwords are always sensitive, for example, "ExamplePassword" and "examplepassword" are two different passwords.
Sometimes the internet connection is broken and we are unaware of it. In case of login failure, make sure your internet connection is live.
The website you are trying to access that does not open may be under maintenance. You may consider trying to access it after some time. Server administrators usually send emails to all registered users about the scheduled upcoming maintenance, especially if you are using an academic portal or employee portal etc. So checking your email may also help you to understand why the website is down or why you are not able to sign in into the site.
Some websites do not allow visitors to access them using a Virtual Private Network. Do not use a VPN to make sure you are not facing the problem because of this issue.