Here are some manual test cases for a login page:

1. Verify that the correct URL opens the login page
2. Check that the correct page title is displayed for the login page
3. Validate that the login form is displayed and contains the expected fields (e.g. username, password)
4. Verify that the input fields only accept valid characters (e.g. no special characters in the username field)
5. Test the error message displayed when an incorrect username or password is entered
6. Verify that the password field is masked (e.g. ***)
7. Check that the user is redirected to the appropriate page after successful login
8. Validate that the “Remember Me” checkbox works as expected
9. Verify that the user can reset their password if they have forgotten it
10. Test the login functionality with both valid and invalid input on both mobile and desktop devices.
11. Check that the login page is secure (e.g. SSL enabled)
12. Validate that the login functionality works on different browsers (e.g. Chrome, Firefox, Safari, etc.)
13. Verify that the user is logged out after a set amount of time (e.g. 30 minutes)
14. Test the login functionality with different types of accounts (e.g. new accounts, existing accounts, etc.)
15. Validate that the correct error message is displayed when an invalid username or password is entered multiple times
16. Verify that the login functionality works even if the network is slow or unstable
17. Test the login functionality with different types of input (e.g. long username, special characters, etc.)
18. Validate that the user is redirected to the appropriate page after logging out
19. Verify that the user can still access the login page after logging out
20. Check that the login page is accessible for users with disabilities (e.g. screen readers).